
____________________________IMPORTANT_NOTICE____________________________

The ownership of a signal descrambler does NOT give the owner the right
to decode or view any scrambled signals without authorization from the
proper company or individual.  Use of such a device without permission
may be in violation of state and/or federal laws.  The information
contained herein is intended to serve as a technical aid to those person
seeking information on various scrambling techniques.  No liability by
myself or my employer is assumed for the (mis)use of this information.
________________________________________________________________________
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

_________________________Scrambling_Technologies________________________

................No Scrambling (Traps/Addressable Taps)..................
A cable system may not be scrambled at all. Some older systems (and many
apartment complexes) use "traps" or "filters" which actually REMOVE the
signals you aren't paying for from your cable. (These are negative traps
because they remove the WHOLE signal.) These systems are relatively
secure because the traps are often located in locked boxes, and once
a service technician finds out they're missing or have been tampered
with (by pushing a pin through a coax trap it to change its frequency,
for example), it's a pretty solid piece of evidence for prosecution.
Another method is where the head-end ADDS an extraneous signal about
2.5 MHz above the normal visual carrier which causes a tuner to think
its receiving a very strong signal--the tuner then adjust the automatic
gain control and buries the real signal. If you pay for the service, the
cable company adds a "positive trap" which then REMOVES the extraneous
injected signal so it becomes viewable. (This system is very easy to
circumvent by building your own notch filter, so it is not very commonly
used.) Advantages to a cable system with this technology is that you
don't need a cable box--all your cable-ready TVs, VCRs, etc. will all
work beautifully. The disadvantage is that pay-per-view events are not
possible, and that every time someone requests a change in service, a
technician has to be dispatched to add/remove the traps.

An article for building a tunable notch filter to block data
streams sent just above the FM band was in the April 1992 issue of
Radio-Electronics (pp. 37-39). Notch filters (as well as kits for
them) for other frequencies are frequently advertised in Nuts & Volts
magazines as "beep" filters and the like.

Becoming more and more popular, not only because of the Cable Act of
1992 but also in an effort to stop "pirates" are addressable taps. Many
cable companies will be moving to this technology in the near future,
(which they call "interdiction"). These are devices located at the pole,
where your individual cable feed is tapped from the head-end. Similar
to addressable converters, they each have a unique ID number and can be
turned on/off by a computer at the head-end. Any stations which you are
not paying for are filtered out by electronicly switchable traps in the
units. (Including the whole signal if you haven't paid your bill or had
the service disconnected.) {Several patents have already been issued for
various methods of making SURE you don't see a channel you don't pay
for.} Again, these almost GUARANTEE an end to piracy and don't have any
of the disadvantages of the manual traps. Plus, they provide a superior
signal to those customers paying for service because they no longer need
complicated cable boxes or A/B switches -- and they can finally use all
of the "cable-ready" capabilites of the VCR, TV, etc. About the only
known attack on this type of system is to splice into a neighbors cable,
which again provides plenty of physical evidence for prosecution.

...............................Sine-Wave................................
Early Oak (and some very early Pioneer boxes) employed a sine-wave sync
suppresion system. In this system, the picture would remain vertically
stable, but wiggling black bars with white on either side would run
down the center of the screen. The lines were caused by a 15,750 Hz
sine-wave being injected with the original signal, causing the sync
separator in the TV to be unable to detect and separate the sync pulses.
Later, Oak came out with a "Vari-Sync" model, which also removed a
31,500 Hz sine-wave added to the signal. Oak was one of the first to
use extra signals ("tags") as a counter-measure for pirate boxes -- in
the normal mode, a short burst of a 100 KHz sine-wave (the tag signal)
would be sent during the VBI, along with the AM sine-wave reference
on the audio carrier and scrambled video. They would then put the AM
sine-wave reference signal onto the audio carrier, leave the video
alone, and NOT send the tag. Any box which simply looked for the AM
sine-wave reference would effectively scramble the video by adding a
sine-wave to the unscrambled video! Real decoders looked for the tag
signal and still worked correctly. Other combinations of tag/no tag,
scrambled/unscrambled video were also possible.

.....................6 dB In-Band Sync Suppression......................
Early Jerrold boxes used in-band gated sync suppression. The horizontal
blanking interval was suppressed by 6 dB. A 15.734, 31.468 or 94.404
KHz reference signal (conveniently all even multiples of the horizontal
sync frequency) was modulated on the sound carrier of the signal, and
used to reconstruct the sync pulse. An article in February 1984 issue
of Radio-Electronics explains this somewhat-old technique. Converters
which have been known to use this system include the Scientific-Atlanta
8500-321/421, a number of Jerrold systems [see numbering chart], Jerrold
SB-#, SB-#-200, SB-#A, RCA KSR53DA, Sylvania 4040 and Magnavox Magna
6400.

...................Tri-mode In-Band Sync Suppression....................
A modification to the 6dB sync suppresion system, dubbed "tri-mode",
allows for 0, 6 and 10 dB suppression of the horizontal sync pulse. The
three sync levels can be varied at random (as fast as once per field),
and the data necessary to decode the signal is contained in unused lines

during the VBI (along with other information in the cable data stream.)
See the February 1987 issue of Radio-Electronics for a good article
(both theory and schematics) on the tri-mode system. Converters which
have been known to use this system include a number of Jerrold systems
[see numbering chart], Jerrold SBD-#A, SBD-#DIC, Jerrold Starcom VI
(DP5/DPV models), Regency, Scientific- Atlanta 8550-321 {anyone know any
others for sure?} and early Pioneer systems {anyone know for sure which
ones?}.

.......................Out-Band Sync Suppression........................
Out-band gated sync systems also exist, such as in early Hamlin
converters. In this system, the reference signal is located on an
unused channel, usually towards the higher end (channels in the 40's
and 50's are common, but never in the low 30's due to potential false
signalling.) The signal is comprised of only sync pulse information
without any video. Tuning in such a channel will show nothing but a
white screen and will usually have no audio.

.............................SSAVI / ZTAC...............................
SSAVI is an acronym for Synchronization Suppression and Active Video
Inversion and is most commonly found on Zenith converters. ZTAC is an
acronym for Zenith Tiered Addressable Converter. Besides suppressing
sync pulses in gated-sync fashion, video inversion is used to yield
four scrambling modes (suppressed sync, normal video; suppressed sync,
inverted video; normal sync, inverted video; and normal sync, normal
video). The horizontal sync pulses of an SSAVI signal can be absent
completely, at the wrong level, or even present, and can be varied on
a field-by-field basis. Any decoder for an SSAVI (or similar) system
has to be able to separate a video line into its two basic components--
the control and picture signals. In SSAVI, the horizontal sync is never
inverted, even if the picture is. So a method of inverting the picture
without inverting the control section is necesary. This is complicated
by the fact that almost every line in an SSAVI signal has no horizontal
sync information, making it difficult to perform the separation (since
the usual reference point--the horizontal sync pulse--is gone). In the
older suppressed-sync system, the sync pulse could be recovered from the
gating signal buried in the audio subcarrier, but SSAVI is "pilotless".
The key to this system relies on the strict timings imposed by the NTSC
standard--if you can locate one part of the signal accurately, you
can determine where everything else should be mathematically. Since
the cable company is sending a digital data stream---the security and
access-rights--during the VBI of the signal, the VBI makes a great place
to find a known point in the signal. Obviously if the electronics in the
cable box can locate this information, so can electronics outside the
cable box! :-)

The only constant in the SSAVI system are the horizontal sync pulses
during the VBI (the first 26 lines of video), which are sent "in the
clear". The pulses from the VBI can be used as a reference for a
phase-locked loop (PLL) and used to supply the missing pulses for the
rest of the video frame. With 20 or so reliable pulses at the beginning
of each frame, you can accurately generate the missing 240 or so pulses.
Of the 26 lines in the VBI, lines zero through nine are left alone by
request of the FCC, lines 10 to 13 are commonly used to transmit a
digital data stream, line 21 contains closed-caption information, while
other lines are used for a variety of "stuff" depending on the cable
system and the channel you're watching. When you tune to a scrambled
channel with a cable box, logic circuits in the unit count the video
lines, read the transmitted data stream, and compare the transmitted
data with the information stored in the box. If the box is authorized
to receive the signal with that particular data stream, the decoder
is enabled and the scrambled signal becomes viewable. If not, the
signal is passed through without being decoded, or more commonly, a
"barker" channel (whose channel number is sent via the data stream) is
automatically tuned instead. This prevents people from using the unit
as a tuner for "add-on descramblers" often advertised in the back of
electronics magazines.

In the SSAVI system, the video can be sent with either normal or
inverted picture information. The descrambler needs a way to determine
whether to invert the video or not. Originally this information could
be found on line 20, but has since moved around a lot as the popularity
(and knowledge) of the system increased. In any event, the last half of
the line would tell the decoder whether to invert the picture or not. If
the rest of the field was not inverted, the last half of the line would
be black. If the video in the rest of the frame was inverted, the last
half of the line would be white.

The Drawing Board column of Radio-Electronics starting in August '92
and going through May '93 described the system and provided several
circuits for use on an SSAVI system. Note that audio in the system can
be "scrambled" - usually by burying it on a subcarrier that's related
mathematically to the IF component of the signal.

Addressable data for Zentih systems is sent in the VBI, lines 10-13,
with 26 bits of data per line.

..............................Tocom systems.............................
The Tocom system is similar to the Zenith system since it provides three
levels of addressable baseband scrambling: partial video inversion,
random dynamic sync suppression and random dynamic video inversion.
Data necessary to recover the signal is encrypted and sent during lines
17 and 18 of the VBI (along with head-end supplied teletext data for
on-screen display). The control signal contains 92 bits, and is a 53 ms
burst sent just after the color burst. Up to 32 tiers of scrambling can
be controlled from the head-end. Audio is not scrambled.

..........................New Pioneer systems...........................
The newer 6000-series converters from Pioneer supposedly offer one
of the most secure CATV scrambling technologies from a "major" CATV
equipment supplier. From the very limited information available on the
system, it appears that false keys, pseudo-keys and both in-band and
out-band signals are used in various combinations for a secure system.
From U.S. patent abstract #5,113,441 which was issued to Pioneer in
May '92 (and may or may not be used in the 6000-series converters, but
could be), "An audio signal is used on which a key signal containing
compression information and informaton concerning the position of a
vertical blanking interval is superimposed on a portion of the audio
signal corresponding to a horizontal blanking interval. In addition,
a pseudo-key signal is superimposed...so that the vertical blanking
interval cannot be detected through the detection of the audio signal...
Descrambling can be performed by detecting the vertical blanking
interval based on the information...in the key signal, and decoding
the information for the position which is transmitted in the form of
out-band data. Compression information can then be extracted from
the key signal based on the detected vertical blanking interval, and
an expansion signal for expanding the signal in the horizontal and
vertical blanking periods can be generated." {If anyone has any better
information on the 6000-series scrambling technique, please send mail!}

Note that Pioneer boxes are "booby-trapped" and opening the unit will
release a spring-mechanism which positively indicates access was gained
to the interior (and sends a signal to the head-end on a two-way system,
and may disable the box completely.) {See U.S. patent #4,149,158 for
details.} The unit cannot be reset without a special device.

Pioneer systems transmit their addressing data on 110.0 MHz.

.....................New Scientific-Atlanta Systems.....................
Some of the early S-A boxes used 6 dB only sync suppression (some of
the 8500 models), and some of the 8550 boxes are tri-mode systems.
The three digit number after the model (such as 321) is a code which
indicates the make of the descrambler in the unit. Apparently some of
the newer S-A boxes use a technique called "dropfield". {If anyone has
more information on any of the 85xx-series or the 8600^x boxes, or an
explanation of "dropfield", send mail...}

Scientific-Atlanta systems transmit their addressing data on 106.2 or
108.2 MHz.

............................Oak "Sigma" Systems.........................
This a secure system which replaces the horizontal sync of each line
of video with a three-byte digital word. Video is switched from
inverted to non-inverted between scene changes, and the colorburst
frequency is shifted "up". This is a standard "suppressed" sync
video scrambling method and is relatively simple to defeat with the
appropriate circuitry. HOWEVER, the three-byte digital word in the
area where the sync normally is contains audio and sync information.
The first two bytes contain a digitized versions of the audio, the
third byte contains sync information (and perhaps addressing data?) The
two bytes of digitized audio are encrypted; a separate carrier signal
contains the decryption keys for the digital audio datastream.

............................Jerrold Baseband............................
No information on techniques used by Jerrold "baseband" converters. {If
anyone has information on other Jerrold scrambling methods other than
those mentioned above, send mail.}

...............................Chameleon................................
The research and development division of Fundy Cable Ltd., NCA
Microelectronics, has a systemd dubbed "Chameleon". They claim it is
a cost-effective solution that prevents pay TV theft by digitally
encrypting the video timing information of sync suppression systems. The
company claims the technology has been proven to be effective against
pirate and tampered boxes. Supposedly, existing decoders can be upgraded
to Chameleon technology with a low-cost add-in circuit, and that the
card's sealed custom IC, developed by NCA, is copy-proof.

..............................VideoCipher...............................
The VideoCipher system is now owned by General Instrument and is used
primarily for satellite signals at this time. VideoCipher I is the
"commercial" version which uses DES (Data Encryption Standard)-encrypted
audio AND video. A VCI descrambler is not available for "home" owners.
VideoCipher II is the now-obsolete system which used a relatively simple
video encryption method with DES-encrypted audio. (Specifically, the
audio is 15 bit PCM, sampled at ~44.1 KHz. It is mu-law companded to
10 bits before transmission.) This has recently been replaced by the
VideoCipher II+, which has been incorporated as the 'default' encryption
method used by VideoCipher IIRS (a smart-card based, upgradeable
system). Supposedly, coded data relating to the digitized, encrypted
audio is sent in the area normally occupied by the horizontal sync
pulse in the VCII system. (The Oak Sigma CATV system uses a similar
technology.) Several methods existed for pirating the VCII based system,
and some SUPPOSEDLY exist for the new VCII+ format, although this has
never been verified. See the rec.video.satellite FAQ list for more
information.

.........................DigiCable/DigiCipher...........................
DigiCipher is an "upcoming" technology being developed by General
Instrument for use in both NTSC and HDTV environments. The DigiCipher
format is for use on satellites, and the DigiCable variation will
address CATV needs. It provides compression algorithms with forward
error correction modulation techniques to allow up to 10 "entertainment
quality" NTSC channels in the space normally occupied by one channel.
It provides true video encryption (as opposed to the VCII-series which
only DES encrypts the audio). In a Multiple Channel Per Carrier (MCPC)
application, the data rate is ~27 MB/second via offset QPSK modulation.
Audio is CD-quality through Dolby AC-2 technology, allowing up to four
audio channels per video channel. The system uses renewable security
cards (like the VCIIRS), has 256 bits of "tier" information, copy
protection capability to prevent events from being recorded, commercial
insertion capability for CATV companies, and more. The multichannel NTSC
satellite version of DigiCipher started testing in July of 1992, and
went into production several months later.

................................B-MAC...................................
MAC is an acronym for Mixed Analog Components. It refers to placing TV
sound into the horizontal-blanking interval, and then separating the
color and luminance portions of the picture signal for periods of 20
to 40 microseconds each. In the process, luminance and chrominance are
compressed during transmission and expanded during reception, enlarging
their bandwidths considerably. Transmitted as FM, this system, when used
in satellite transmission, provides considerably better TV definition
and resoluton. Its present parameters are within the existing NTSC
format, but is mostly used in Europe at this time. {Does anyone know
if the D2-MAC system is just a variation of this, or is it completely
different? What's new in the D2-MAC system?}

________________________Miscellaneous_Information_______________________

.........................Two-Piece vs. One-Piece........................
There are both advantages and disadvantages to the one-piece and
two-piece descramblers often advertised in the back of electronics
magazines. The "one-piece units" are real cable converters, just
like you'd get if you rented one from the cable company. It has the
advantages of "real" descrambling circuitry and the ability to "fit-in"
well when neighbors come over (avoids those "my box doesn't look like
that...or get all these channels!" conversations :-) A disadvantage is
that if you move or the cable company installs new hardware, you may now
have a worthless box -- most one-piece units only work on the specific
system they were designed for. Another disadvantage is that if the box
has not been modified, it can be very easy for the head-end to disable
the unit completely. (See Market Codes & Bullets, below.)

A "two-piece unit" ("combo") usually consists of an any-brand cable TV
tuner with a third-party "descrambler" (often referred to as a "pan")
which is designed to work with a specific scrambling technology. The
descrambler typically connects to the channel 3 output of the tuner,
and has a channel 3 output which connects to your TV. (Although some
tuners have a "decoder loop" for such devices.) They have the advantage
that if you move or your system is upgraded, you can try to purchase a
new descrambler -- which is much cheaper than a whole new set-up. You
also can select the cable TV tuner with the features you want (remote,
volume control, parental lockout, baseband video output, etc.) Two-piece
units typically cannot be disabled by the data stream on your cable.
(Note however that there ARE add-on "pans" manufactured by the same
companies who make the one-piece units that DO pay attention to the data
stream and can be disabled similarly!) The main disadvantage is that a
third-party descrambler MAY not provide as high of quality descrambling
as "the real thing", and it may arrouse "suspicion" if someone notices
your "cable thing" is different from theirs.

........................Jerrold Numbering System........................
To decode older Jerrold converters, the following chart may be helpful.
(Note that some spaces may be blank.) {Send along any additions or other
numbering systems you know of!}

 __ __ __ __ - __ __ __
 |  |  |  |    |  |  |
 |  |  |  |    |  |  |___ T = two-way capability, C = PROM programmable
 |  |  |  |    |  |
 |  |  |  |    |  |______ DI = Inband decoder, DO = Outband decoder,
 |  |  |  |    |          PC = Single pay channel, A = Addressable
 |  |  |  |    |
 |  |  |  |    |_________ Output channel number (3 very common)
 |  |  |  |
 |  |  |  |______________ D or I = tri-mode system, N = parental lockout
 |  |  |                    feature (6 dB-only systems are "blank" here)
 |  |  |
 |  |  |_________________ M = mid-band only, X = thru 400 MHz,
 |  |                     Z = thru 450 MHz, BB = baseband
 |  |
 |  |____________________ S = Set-top, R = Remote
 |
 |_______________________ D = Digital tuning, J = Analog tuning

Also note that some Jerrold converters (particularly the DP5 series
and maybe others) have a tamper-switch, and that opening the box will
clear the contents of a RAM chip in the converter. This may or may not
be corrected by letting the unit get "refreshed" by the head-end data
stream.

Most Jerrold systems transmit their addressing data near 97.5, 106.5 or
108.5 MHz.  The datastream is Manchester encoded FSK, with approximately
a 14kHz clock.

................Scientific-Atlanta Suppressed Sync Boxes................
Model 8600 - _ _ _ _
             | | | |
             | | | |___ Impulse PPV Return: N=none, T=telephone, R=RF
             | | |_____ Dual cable option: N=none, D=dual cable
             | |_______ Descrambler type: S=SA standard, K=oak
             |_________ Channel: S=selectable channel 3/4
   The 8600 has 240 character on-screen display, multimode scrambling,
   8 event 14 day timer, and is "expandable"...

Model 859_ - 7 _ 7 _
         |     |   |
         |     |   |__ Dual cable option: D=dual cable
         |     |______ Descrambler: 5=SA scrambling+video inversion,
         |                          7=5+Oak
         |____________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV
   The 8590s feature volume control, multimode scrambling, 8 event
   14 day timer...

Model 858_ - _ 3 _ - _
         |   |   |   |__ Dual cable option: D=dual cable
         |   |   |______ Data carrier: 6=106.2 MHz, 8=108.2 MHz
         |   |__________ Channel: 3=channel 3, 4=channel 4
         |______________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV
   The 8580s use dynamic sync suppression, 8 event 14 day timer, and
   built-in pre-amp.

The 8570 is similar to the 8580.

Model 8550 - _ _ _
             | | |__ 1=108.2 MHz data stream
             | |____ Jerrold, dropfield, SA descrambling
             |______ Channel: 3=channel 3
   The 8550 is not a current model; it can be replaced with an 8580-321.

Non-addressable products include the 8511, 8536, and 8540.

{If anyone has more details/corrections, please send them along.}

.............................Market Codes...............................
Note that almost every addressable decoder in use today has a unique
"serial number" programmed into the unit -- either in a PROM,
non-volatile RAM, EAROM, etc. This allows the head-end to send commands
specifically to a certain unit (to authorize a pay-per-view events, for
example.) Part of this "serial number" is what is commonly called a
"market code", which can be used to uniquely identify a certain cable
company. This prevents an addressable decoder destined for use in
Chicago from being used in Houston. In most cases, when a box receives a
signal with a different market code, it will enter an "error mode" and
become unusable. This is just a friendly little note to anyone who might
consider purchasing a unit from the back of a magazine -- if the unit
has not been "modified" in any way to prevent such behavior, you could
end up with an expensive paper weight... (see next section)

.............................Test Chips.................................
So-called "test chips" are used to place single-piece converters (that
is, units with both a tuner and a descrambler) into full service. There
are a number of ways to accomplish this, but in some cases, the serial
number/market code for the unit is set to a known "universal" case
or, better yet, the comparison checks to determine which channels to
enable/disable are bypassed by replacing an IC in the unit. Hence, the
"descrambler" will always be active, no matter what. This latter type of
chip is superior because it cannot be disabled and is said to be "bullet
proof", even if the cable company finds out about a "universal" serial
number. (When the cable company finds out about a universal serial
number, it is easy for them to disable the converter with a variation on
the "bullet" described below.)

................................Cubes...................................
Another type of "test device" has been advertised in magazines such as
Electronics Now (formerly Radio-Electronics) and Nuts & Volts. It's
called a "cube" and it SIMULATES the addressing data signal for a cable
box, most commonly for those from Pioneer and Jerrold (the Zenith data
stream is sent in the VBI, making this apporach more difficult). You
plug the cable into one side, where it filters out the real data signal,
and out the other side comes a normal signal, but with a new data
stream. (There are also "wireless" cubes which you just periodically set
near your box with the cable disconnected to "refresh" it.)

This new data signal tells whatever boxes the cube addresses to go
into "full-service" mode (including any cable company-provided boxes).
Sometimes it is a non-destructive signal, and if the the "cube" is
removed from the line, the real data signal gets to the electronics
inside and the converter goes back to normal "non-test" mode. Note
that sometimes it IS destructive: there are some cubes that re-program
the electronic serial number in a converter to a new value. This type
has the advantage that it will work with any converter the cube was
designed to test (but changes the serial number to some "preset" value).
The "non-destructive" versions of a cube usually require that you
provide the serial number from the converter you're interested in
"testing". That way a custom IC can be programmed to address that
converter with the necessary data. (Otherwise the converter would ignore
the information, since the serial number the cube was sending and the
one in converter wouldn't match.)

...............................Bullets..................................
First and foremost, THE "BULLET" IS NOTHING MORE THAN THE NORMAL CABLE
DATA STREAM WITH THE APPROPRIATE "CODE" TO DISABLE A CONVERTER WHICH
HAS NOT BEEN ACKNOWLEDGED BY THE CABLE COMPANY. For instance, the head
end could send a code to all converters which says "unless you've been
told otherwise in the last 12 hours, shut down." All legitimate boxes
were individually sent a code to ignore this shut down code, but the
pirate decoders didn't get such a code because the cable company doesn't
have their serial number. So they shut down when the see the "bullet"
code.

The "bullet" is NOT a harmful high-voltage signal or something as
the cable companies would like you to believe -- if it was, it would
damage anyone with a cable-ready TV or VCR connected to the cable (not
something the cable company wants to deal with!)

The only way to get "caught" by such a signal is to contact the cable
company and tell them your illegal descrambler just quit working for
some reason. :-) Not a smart thing to do, but you'd be surprised,
especially if it's someone else in the house who calls, like a spouse,
child, babysitter, etc.  While we're on the subject, it's also not a
good idea to have cable service personnel come into your residence and
find an unauthorized decoder...

.............Time Domain Reflectometry / Leak Detection.................
The cable company can use a technique called "Time Domain Reflectometry"
(TDR) to try and determine how many devices are connected to your cable.

In simple terms, a tiny, short test signal is sent into your residence
and the time domain reflectometer determines the number of connections
by the various "echoes" returned down the cable (since each device
is at a different point along the cable, they can be counted.) Each
splitter, filter, etc. will affect this count. A simple way to avoid
being "probed" is to install an amplifier just inside your premises
before any connections. This isolates the other side of the cable from
the outside, and a TDR will only show one connection (the amplifier).

The cable company also has various ways of detecting signal "leaks"
in their cable. The FCC REQUIRES them to allow only so much signal to
be radiated from their cables. You may see a suspicious looking van
driving around your neighborhood with odd-looking antennas on the roof.
These are connected inside to field strength meters which help locate
where the leaks are coming from so they can be fixed (to prevent a
fine from the FCC!) If you've tampered with a connection at the pole
(say, to hook up a cable that had been disconnected) and didn't do a
good job, chances are the connection will "leak" and be easily found by
such a device. This can also happen INSIDE your residence if you use
cheap splitters/amplifiers or have poorly-shielded connections. The
cable company will ask to come inside, and bring with them a portable
field strength meter to help them locate the problem. Often they will
totally remove anything causing the leak, and may go further (e.g.,
legal action) if they feel you're in violation of your contract with
them (which you agree to by paying your bill.) Obviously it's a bad
idea to let cable service personnel into your house if you ARE doing
something you shouldn't (which you shouldn't be in the first place), but
if you DON'T let them in (as is your right), it will definitely arouse
suspicion. Eventually you will have to let them in to fix the "leak", or
they will disconnect your cable to stop the leak altogether. (After all,
it's a service, not a right, to receive cable!)

...................Some Common Ways Pirates Get Caught..................
There are many ways for a "pirate" to get caught. Since stealing cable
is illegal in the U.S., you can be fined and sent to jail for theft of
service. Cable companies claim to lose millions of dollars in revenue
every year because of pirates, so they are serious in their pursuit of
ridding them from their system.

 . a pirate will often show-off the fact they can get every channel
   to their friends. Pretty soon lots of people know about it, and then
   the cable company offers a "Turn In A Pirate And Get $50" program. A
   "friend" needs the money and turns the pirate in...

 . a pirate (or more likely, unsuspecting housemate of a pirate who
   knows nothing about whats going on) calls the cable company to report a
   problem with the equipment or signal. The cable company makes a service
   call and finds gray-market equipment connected to the cable...

 . during a pay-per-view event such as a fight, the cable company offers
   a free T-shirt to all viewers. Little does the pirate know that just
   before that message appeared on the screen, legitimate viewer's boxes
   were told to switch to another channel WHILE STILL DISPLAYING THE
   ORIGINAL CHANNEL NUMBER (yes, cable boxes can do this.) So now the
   legitimate subscriber continues to see the "original" signal (without
   the T-shirt offer), while the pirate gets an 800 number plastered on
   the screen. The pirate calls, and the cable company gets a list of all
   potential pirates...

 . the cable company temporarily broadcasts some soft-core pornography
   onto what is supposed to be The Disney Channel (and vice-versa). They
   simultaneously reprogram subscriber converters to re-map the channels
   correctly, so the change is transparent to all but non-company
   converters. Those who call to complain about the "non-Disney"
   entertainment (or cartoons on the Playboy channel :-) are more than
   likely to have gray-market decoders...

 . a big cable descrambler business gets busted. The authorities
   confiscate their UPS shipping records and now have a list of
   "customers" who most likely ordered descramblers for illegitimate
   use...

And this is only the beginning. Unconfirmed reports of the cable company
driving around with special equipment allowing them to determine what
you're watching on your TV (like HBO, which you don't pay for) have also
been mentioned.

Of course, the best thing to do is simply PAY FOR WHAT YOU WATCH!  Then
you don't have to worry about the possibility of a prison term, criminal
record, hefty fine, etc.

........................The Universal Descrambler.......................
In May of 1990, Radio-Electronics magazine published an article on
building a "universal descrambler" for decoding scrambled TV signals.
There has been much talk on the net about the device, and many have
found it to be lacking in a number of respects. Several modifications,
hoping to fix some of the problems have also been posted, with limited
success. The Universal Descrambler relies on the presence of the
colorburst for its reference signal. In a normal line of NTSC video,
the colorburst is 8 to 11 cycles of a 3.579545 MHz clock (that comes
out to 2.31 microseconds) which follows the 4.71 microsecond horizontal
sync during the horizontal blanking interval. {Whew!} Since a large
number of scrambling systems depend on messing with the horizontal sync
pulse to scramble the picture, the Universal Descrambler attempts to
use the colorburst signal to help it replace the tainted sync pulse.
Unfortunately, random video inversion is still a problem, as are color
shifts which occur from distorted or clamped colorburst signals, etc.
Most people have not had very good results from the system, even after
incorporating some modifications.

________________________Glossary_of_Related_Terms_______________________
{Suggestions or contributions to the glossary are welcome!}

CATV:   Acronym for Community Antenna TeleVision. Originally cable TV
        came about as a way to avoid having everyone in a community have
        to spend a lot of money on a fancy antenna just to get good TV
        reception.  Really all you need is one very good antenna and
        then just feed the output to everyone.  It was called Community
        Antenna Television (CATV).  Of course, it has grown quite a bit
        since then and everyone now just calls it cable TV.  The old
        acronym still sort-of works.
Converter:
        A device, sometimes issued by the cable company, to "convert"
        many TV channels to one specific channel (usually channel 3).
        Used early-on when VHF & UHF channels were on different dials
        (and before remote controls) to provide "convenience" to cable
        customers.  Now mostly considered a nuisance, thanks to the
        advent of cable-ready video equipment, they are mainly used as
        descramblers.
        An "addresable" converter is one that has a unique serial number
        and can be told (individually) by the head-end to act in a
        certain manner (such as enabling channel x, but not channel y).
        Addressable converters nearly always contain descramblers for
        decoding premium services subscribed to by the customer.
Colorburst:
        Approximately 8 to 10 cycles of a 3.579545 MHz clock sent during
        the HBI.  This signal is used as a reference to determine both
        hue and saturation of the colors.  A separate colorburst signal
        is sent for each line of video, and are all exactly in phase (to
        prevent color shifts).
Control Signal:
        The first 11.1 microseconds of a line of NTSC video.  The signal
        area from 0 to 0.3 volts (-40 to 0 IRE units) is reserved for
        control signals, the rest for picture information.  If the
        signal is at 0.3 volts (or 0 IRE) the picture will be black.
        See IRE Units; Set-up Level.
Field:  One half of a full video frame.  The first field contains
        the odd numbered lines, the second field contains the even
        numbered lines.  Each field takes 1/60th of a second to
        transmit.  Note that both fields contain a complete
        vertical-blanking interval and they both (should) have the same
        information during that interval.  Since the NTSC standard is
        525 lines, each field contains 262.5 lines--therefore it's the
        half-line that allows the two fields of a frame to be
        distinguished from one another.  See Frame; Line.
Frame:  An NTSC video signal which contains both fields.  A frame
        lasts 1/30th of a second.  See Field; Line.
Head-end:
        The main cable distribution facility where your CATV signal
        originates from.  (Easily identifed by several large satellite
        dishes, some smaller ones, and usually an antenna tower.)
HBI:    Acronym for Horizontal Blanking Interval.  The first 11.1
        microseconds of a line of video.  It contains the front porch,
        the 4.71 microsecond horizontal sync pulse, the 2.31
        microseconds of colorburst, and the back porch.  The horizontal
        sync pulse directs the beam back to left side of the screen.
        Almost every scrambling method in use today mutataes this part
        of the signal in some way to prevent unauthorized viewing.  See
        Colorburst.
Interlace:
        Term used to describe the dual-field approach used in the NTSC
        standard.  By drawing every other line, screen flicker is
        increased--but if all the lines were painted sequentially, the
        top would begin to fade before the screen was completely "painted".
        (Computer monitors, which do "paint" from top to bottom, do not
        have the problem due to higher refresh rates.)
IPPV:   Impulse Pay-Per-View.  A method whereby a viewer can order a
        pay-per-view event "on impulse" by just pushing an "Order" (or
        similar) button on a remote control or cable converter keypad.
        A customer's purchases are sent back to the head-end via a
        standard telephone connection (the converter dials into the cable
        co. computer and uploads the data) or via radio frequency (RF) if
        the cable supports two-way communication (most don't).  A pre-set
        maximum number of events can be ordered before the box requires
        the data to be sent to the head-end for billing purposes.
IRE Units:
        IRE is an acronym for Institure of Radio Engineers.  The NTSC
        standard calls for a peak-to-peak signal voltage of 1 volt.
        Instead of referring to the video level in volts, IRE units are
        used instead.  The IRE scale divides the 1- volt range into 140
        parts, with zero-IRE corresponding to about 0.3V.  The full
        scale goes from -40 IRE to +100 IRE.  This is convenient scale
        to make a distinction between control signals (< 0 IRE) and
        picture signals (> 0 IRE).  See Control Signal.
Line:   A video signal is a series of repeated horizontal lines,
        consisting of control and picture information.  The color NTSC
        standard allows a total time of 63.56 microseconds for each
        line, and each frame is composed of 525 lines of video
        information.  The first 11.1 microseconds make up the horizontal
        blanking interval, or control signal, the following 52.46
        microseconds make up the picture signal.  See HBI; VBI.
NTSC:   Acronym for National Television Standards Committee (or
        Never The Same Color, if you prefer :-)
Picture Signal:
        The 52.46 microseconds of signal following the control signal.
        Information in this area is between 0 and 100 IRE units.  See
        IRE Units.
PPV:    Acronym for Pay-Per-View.  A revenue-enhancing system where
        customer's pay to watch a movie or event on a "per view" basis.
        Cusomers usually place a phone call to a special number and order
        the event of their choice; some systems provide Impulse PPV.
        The presence of a PPV movie channel or your system guarantees
        you have addressable converters.  See IPPV.
Set-up Level:
        Picture information technically has slightly less than 100 IRE
        units available.  That's because picture information starts at
        7.5 IRE units rather than at 0 IRE units.  The area from 0 to
        7.5 IRE units are reserved for what is commonly called the
        "set-up level".  Having a small buffer area between the control
        signal information and the picture information is a "fudge
        factor" to compensate for the fact that real-life things that
        don't always work as nicely as they do on paper. :-)  See IRE
        Units.
VBI:    Acronym for Vertical-Blanking Interval.  The first 26 lines of
        an NTSC video signal.  This signal is used to direct the beam
        back to the upper-left corner of the screen to start the next
        frame.  In order for the horizontal sync to continue operating,
        the vertical pulse is serrated into small segments which keep
        the horizontal circuits active.  Both actions can then take
        place simultaneously.  The VBI is the most common place for
        "extra" information to be sent, such as various test signals,
        and in some cable systems, a data stream.

_______________________Television_Frequency_Chart_______________________

The following chart lists frequency information for the "standard"
carrier sets. HRC (Harmonically Related Carrier) and IRC encoding
methods are slightly different. {Can anyone provide specifics on the
different frequency formats? Ed.}

                   Center  Video    Color    Sound   Osc.
 Channel   Band    Freq.  Carrier  Carrier  Carrier  Freq.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                        VHF-Low Band
 TVIF      40-46     43    41.25    44.83    47.75
    2      54-60     57    55.25    58.83    59.75    101
    3      60-66     63    61.25    64.83    65.75    107
    4      66-72     69    67.25    70.83    71.75    113
    5      76-82     79    77.25    80.83    81.75    123
    6      82-88     85    83.25    86.83    87.75    129
 -----------------------------------------------------------
                        FM (Pseudo)
  FM-1     88-94     91    89.25    92.83    93.75
  FM-2     94-100    97    95.25    98.83    99.75
  FM-3    100-106   103   101.25   104.83   105.75
 -----------------------------------------------------------
                    VHF-Mid Band (CATV)
 A2-(00)  108-114   111   109.25   112.83   113.75    155
 A1-(01)  114-120   117   115.25   118.83   119.75    161
  A-(14)  120-126   123   121.25   124.83   125.75    167
  B-(15)  126-132   129   127.25   130.83   131.75    173
  C-(16)  132-138   135   133.25   136.83   137.75    179
  D-(17)  138-144   141   139.25   142.83   143.75    185
  E-(18)  144-150   147   145.25   148.83   149.75    191
  F-(19)  150-156   153   151.25   154.83   155.75    197
  G-(20)  156-162   159   157.25   160.83   161.75    203
  H-(21)  162-168   165   163.25   166.83   167.75    209
  I-(22)  168-174   171   169.25   172.83   173.75    215
 -----------------------------------------------------------
                       VHF-High Band
    7     174-180   177   175.25   178.83   179.75    221
    8     180-186   183   181.25   184.83   185.75    227
    9     186-192   189   187.25   190.83   191.75    233
   10     192-198   195   193.25   196.83   197.75    239
   11     198-204   201   199.25   202.83   203.75    245
   12     204-210   207   205.25   208.83   209.75    251
   13     210-216   213   211.25   214.83   215.75    257
 -----------------------------------------------------------
                    VHF-Super Band (CATV)
  J-(23)  216-222   219   217.25   220.83   221.75    263
  K-(24)  222-228   225   223.25   226.83   227.75    269
  L-(25)  228-234   231   229.25   232.83   233.75    275
  M-(26)  234-240   237   235.25   238.83   239.75    281
  N-(27)  240-246   243   241.25   244.83   245.75    287
  O-(28)  246-252   249   247.25   250.83   251.75    293
  P-(29)  252-258   255   253.25   256.83   257.75    299
  Q-(30)  258-264   261   259.25   262.83   263.75    305
  R-(31)  264-270   267   265.25   268.83   269.75    311
  S-(32)  270-276   273   271.25   274.83   275.75    317
  T-(33)  276-282   279   277.25   280.83   281.75    323
  U-(34)  282-288   285   283.25   286.83   287.75    329
  V-(35)  288-294   291   289.25   292.83   293.75    335
  W-(36)  294-300   297   295.25   298.83   299.75    341
 -----------------------------------------------------------
                    VHF-Hyper Band (CATV)
 AA-(37)  300-306   303   301.25   304.83   305.75    347
 BB-(38)  306-312   309   307.25   310.83   311.75    353
 CC-(39)  312-318   315   313.25   316.83   317.75    359
 DD-(40)  318-324   321   319.25   322.83   323.75    365
 EE-(41)  324-330   327   325.25   328.83   329.75    371
 FF-(42)  330-336   333   331.25   334.83   335.75    377
 GG-(43)  336-342   339   337.25   340.83   341.75    383
 HH-(44)  342-348   345   343.25   346.83   347.75    389
 II-(45)  348-354   351   349.25   352.83   353.75    395
 JJ-(46)  354-360   357   355.25   358.83   359.75    401
 KK-(47)  360-366   363   361.25   364.83   365.75    407
 LL-(48)  366-372   369   367.25   370.83   371.75    413
 MM-(49)  372-378   375   373.25   376.83   377.75    419
 NN-(50)  378-384   381   379.25   382.83   383.75    425
 OO-(51)  384-390   387   385.25   388.83   389.75    431
 PP-(52)  390-396   393   391.25   394.83   395.75    437
 QQ-(53)  396-402   399   397.25   400.83   401.75    443
 RR-(54)  402-408   405   403.25   406.83   407.75    449
 -----------------------------------------------------------
                         UHF Band
   14     470-476   473   471.25   474.83   475.75    517
   15     476-482   479   477.25   480.83   481.75    523
   16     482-488   485   483.25   486.83   487.75    529
   17     488-494   491   489.25   492.83   493.75    535
   18     494-500   497   495.25   498.83   499.75    541
   19     500-506   503   501.25   504.83   505.75    547
   20     506-512   509   507.25   510.83   511.75    553
   21     512-518   515   513.25   516.83   517.75    559
   22     518-524   521   519.25   522.83   523.75    565
   23     524-530   527   525.25   528.83   529.75    571
   24     530-536   533   531.25   534.83   535.75    577
   25     536-542   539   537.25   540.83   541.75    583
   26     542-548   545   543.25   546.83   547.75    589
   27     548-554   551   549.25   552.83   553.75    595
   28     554-560   557   555.25   558.83   559.75    601
   29     560-566   563   561.25   564.83   565.75    607
   30     566-572   569   567.25   570.83   571.75    613
   31     572-578   575   573.25   576.83   577.75    619
   32     578-584   581   579.25   582.83   583.75    625
   33     584-590   587   585.25   588.83   589.75    631
   34     590-596   593   591.25   594.83   595.75    637
   35     596-602   599   597.25   600.83   601.75    643
   36     602-608   605   603.25   606.83   607.75    649
   37     608-614   611   609.25   612.83   613.75    655
   38     614-620   617   615.25   618.83   619.75    661
   39     620-626   623   621.25   624.83   625.75    667
   40     626-632   629   627.25   630.83   631.75    673
   41     632-638   635   633.25   636.83   637.75    679
   42     638-644   641   639.25   642.83   643.75    685
   43     644-650   647   645.25   648.83   649.75    691
   44     650-656   653   651.25   654.83   655.75    697
   45     656-662   659   657.25   660.83   661.75    703
   46     662-668   665   663.25   666.83   667.75    709
   47     668-674   671   669.25   672.83   673.75    715
   48     674-680   677   675.25   678.83   679.75    721
   49     680-686   683   681.25   684.83   685.75    727
   50     686-692   689   687.25   690.83   691.75    733
   51     692-698   695   693.25   696.83   697.75    739
   52     698-704   701   699.25   702.83   703.75    745
   53     704-710   707   705.25   708.83   709.75    751
   54     710-716   713   711.25   714.83   715.75    757
   55     716-722   719   717.25   720.83   721.75    763
   56     722-728   725   723.25   726.83   727.75    769
   57     728-734   731   729.25   732.83   733.75    775
   58     734-740   737   735.25   738.83   739.75    781
   59     740-746   743   741.25   744.83   745.75    787
   60     746-752   749   747.25   750.83   751.75    793
   61     752-758   755   753.25   756.83   757.75    799
   62     758-764   761   759.25   762.83   763.75    805
   63     764-770   767   765.25   768.83   769.75    811
   64     770-776   773   771.25   774.83   775.75    817
   65     776-782   779   777.25   780.83   781.75    823
   66     782-788   785   783.25   786.83   787.75    829
   67     788-794   791   789.25   792.83   793.75    835
   68     794-800   797   795.25   798.83   799.75    841
   69     800-806   803   801.25   804.83   805.75    847
   70     806-812   809   807.25   810.83   811.75    853
   71     812-818   815   813.25   816.83   817.75    859
   72     818-824   821   819.25   822.83   823.75    865
   73     824-830   827   825.25   828.83   829.75    871
   74     830-836   833   831.25   834.83   835.75    877
   75     836-842   839   837.25   840.83   841.75    883
   76     842-848   845   843.25   846.83   847.75    889
   77     848-854   851   849.25   852.83   853.75    895
   78     854-860   857   855.25   858.83   859.75    901
   79     860-866   863   861.25   864.83   865.75    907
   80     866-872   869   867.25   870.83   871.75    913
   81     872-878   875   873.25   876.83   877.75    919
   82     878-884   881   879.25   882.83   883.75    925
   83     884-890   887   885.25   888.83   889.75    931


Archive-name: wireless-cable
Last-modified: Wed, February 2, 1994


***** Wireless Cable Television - Frequently Asked Questions (FAQ) *****

Compiled by Brian J. Catlin
catlin@CS.ColoState.Edu  -or-  bc338569@longs.LANCE.ColoState.Edu

This file is Copyright (C) 1993, 1994 by Brian J. Catlin.  All rights
reserved.  Redistribution of this file, in whole or in part, in both
electronic and printed form, is permitted provided that no fee (other than
direct costs) is charged and that proper credit is given.  If you
redistribute this file on another network, please let me know so that I can
keep track of where this file goes.

NOTE:  Most of this information is taken from FCC Public Notices along with
information sent to me by both the FCC and the Wireless Cable Association
(WCA).  Other information has come from numerous newspapers, magazines, and
from discussions with MMDS subscribers.  Items marked with three plus signs
(+++) have been added or changed since the last posting.
I would also like to thank Alan Larson and Craig Strachman for their
numerous contributions and corrections.

NOTE:  For those of you wanting me to check on companies, please read the
end of section 10.0.

Contents:
     1.0  Abbreviations used
     2.0  What is wireless cable?
     2.1  What is CellularVision?
     3.0  What are the benefits of wireless cable to the customer?
     3.1  How does wireless cable work?
     3.2  What is the history of MMDS?
     3.3  How does MMDS work commercially?
     4.0  What frequencies are used?
     4.1  How many channels can be transmitted?
     4.2  What channels can be sent?
     5.0  What is the range of wireless cable?
     5.1  Does weather affect reception?
     6.0  What equipment is in the subscriber's home?
     6.1  Is wireless cable equipment reliable?
     7.0  What about copyright issues?
     8.0  What about security?
     9.0  How are wireless cable systems regulated?
    10.0  I saw one of those 'infomercials' about wireless cable.  Are
          these companies legit?
    10.1  How can I tell if a company is running a scam on me?
    11.0  Is there an industry association?
    11.1  Who do I contact for more information?


Questions and Answers
---------------------

1.0)  ABBREVIATIONS USED:

    ITFS - Instructional Television Fixed Service.  Channels that must have
           a minimum of 5 hours per week of educational programming.  May
           be leased for wireless cable usage.
    LMDS - Local Multipoint Distribution Service.  Two sets of 50 channels
           in the 28 GHz band.  Not yet available for wireless cable usage.
    MDS  - Multipoint Distribution Service.  Two channels that are similar
           to MMDS.  May be used in a wireless cable system.
    MMDS - Multichannel Multipoint Distribution Service.  Two sets of four
           channels each.  Also, type of service known as "Wireless Cable".
    OFS  - Private Operational-Fixed Microwave Service.  Three channels
           that may be used for a wireless cable system.

2.0)  WHAT IS WIRELESS CABLE?

    Wireless cable is a name given to a service that is called Multichannel
    Multipoint Distribution Service (or MMDS).  It is a type of cable
    television system that offers its subscribers a mix of satellite
    channels by transmitting the programming over MMDS frequencies along
    with MDS, OFS, and ITFS frequencies, if they are available.  Wireless
    cable uses Super High Frequency ("SHF") channels to transmit satellite
    cable programming over-the-air instead of through overhead or
    underground wires.

2.1)  WHAT IS CELLULARVISION?

    CellularVision/Suite12 is a company that has been granted special
    permission by the FCC to transmit video services on a higher frequency
    than what wireless cable uses.  They have recently started testing in
    the 28 GHz (or LMDS) band.  It is believed that the FCC may allocate
    two sets of 50 channels in this band for wireless cable type service.
    CellularVision is hoping to provide television plus much more.  With
    this system it would be possible to have interactive networking,
    grocery ordering, bank transactions, and video teleconferencing.  I am
    not sure what all CellularVision is planning on offering during this
    initial testing period.  However, using the 28 GHz band means
    sacrificing signal range.  These signals aren't able to achieve even
    the 25-30 mile range that MMDS and other 2 GHz services are able to
    get, given the same transmitting power.  To get around this, they are
    using 35 "cell sites" to transmit the programming.  They hope to offer
    service to over 6.3 million subscribers in the region around New York
    City by 1995.

    The signal that they are sending is interleaved, which allows the
    transmission of large numbers of services with narrow bandwidths.

3.0)  WHAT ARE THE BENEFITS OF WIRELESS CABLE TO THE CUSTOMER?

    Availability:  Wireless Cable can be made available in areas of
    scattered population and other areas where it is too expensive to build
    a traditional cable station.

    Affordability:  Due to the lower costs of building a Wireless Cable
    Station, savings can be passed on to the subscribers.

3.1)  HOW DOES IT WORK?

    Scrambled satellite cable programming is received at a central location
    where it is processed and fed into special transmitters.  The SHF
    transmitters distribute the programming throughout the coverage area,
    The signals are received by special antennas installed on subscribers'
    roofs, combined with the existing VHF and UHF channels from the
    subscriber's existing antenna, and distributed within the home or
    building through coaxial cable into a channel program selector located
    near the television set.

    Notice that you must provide a UHF and/or VHF antenna if you want the
    broadcast channels.  This is because the Wireless Cable Box only
    provides a UHF/VHF tuner.  Of course, not all boxes include even this
    feature (but most do).

3.2)  WHAT IS THE HISTORY OF MMDS?

    It is a fairly new service that developed from MDS (multi-point
    distribution service) which could only send one or two channels.
    Originally, the FCC thought MDS would be used primarily to send business
    data.  However, since MDS's creation in the early 70's, the service has
    become increasingly popular in sending entertainment programming.
    Because the FCC does not regulate the content of the transmission,
    alternative uses would not be prohibited.

    Today, there are systems in use all around the U.S. and in many other
    countries including the former Soviet Union, Australia (is yours fully
    functional yet?), and Canada.  At the rate that the FCC has been
    receiving applications, it looks as if many more systems are going to be
    built in the U.S..

3.3)  HOW DOES MMDS WORK COMMERCIALLY?

    A MMDS licensee, which is similar to a broadcast station owner, leases
    transmission time to programmers on a first-come, first-served basis.
    The programmers, in turn, are responsible for designing and selling
    their programs to the subscriber.

    A MMDS applicant can choose to operate as a common carrier.  In the
    telecommunications industry, a common carrier also may provide services
    such as audio only transmissions, telephone, or data.  The FCC also
    requires that the licensee and the programmer not be related or
    affiliated.  A common carrier offers transmission service for hire and
    cannot control program material or serve primarily its other business
    interests.  (Note that this is NOT part of what is usually called
    "video dialtone".  However, depending on the technology used, it may
    be possible to provide video dialtone using this method.)

    A MMDS applicant can alternatively choose to operate as a non-common
    carrier.  This scenario in effect would constitute a non-common carrier
    wireless cable system.

    Also, note that a MMDS license only entitles you to FOUR channels.  In
    order to use all 33 channels, you must apply for several different
    licenses from different bureaus of the FCC.  This can be very costly!

4.0)  WHAT FREQUENCIES ARE USED?

    Frequency                    num. of     type of    channel
    Range                        channels    service    groups
    -------------------------    --------    -------    -----------------
    2,150 - 2,162 MHz               2          MDS      1,2,2(A)
    2,500 - 2,596 MHz              16         ITFS      ABC&D
    2,596 - 2,644 MHz               8         MMDS      E&F
    2,644 - 2,686 MHz               4         ITFS      G
      "   -   "                     3          OFS      H
    2,686 - 2,689.875 MHz          31*        MMDS      Response Channels

    * - Each channel's bandwidth is 125 KHz, and does not carry video.

    There are also tests being made in New York for transmitting in the
    28 GHz band (LMDS).  The frequencies used are 27.5 GHz - 29.5 GHz.
    I am not sure of how these frequencies are divided between the
    different services.

4.1)  HOW MANY CHANNELS CAN BE TRANSMITTED?

    When fully implemented, wireless cable operations may have as many as
    33 channels of broadcast and cable programming.  This, of course,
    depends on which channels are already used in your area.  Furthermore,
    20 of the 33 channels are borrowed from ITFS services and are earmarked
    for educational use.  This means there is a requirement to program 5
    hours per week per channel of educational material.  If any of these
    channels are being used, then any extra time can be leased by the MMDS
    station, if the owner of the license agrees.

    Approximately 90 to 150 channels may become available if digital
    compression is used.  There are a few sites that are getting ready to
    test this new technology, so we'll have to wait and see how things go.
    Also, since the signals will be sent digitally, it is expected that the
    range of the signal will increase by approximately 3 times.

    Zenith has recently demonstrated a 16-level digital transmission system
    that is capable of delivering HDTV (High Definition Television).

    Wireless Cable operators are now allowed to place all of their
    educational programming onto one ITFS channel.  In the past, operators
    have had to use the channel re-mapping function of the downconverters
    to make all of the educational channels appear to be on one channel.
    This greatly simplifies programming issues for the operators.

4.2)  WHAT CHANNELS CAN BE SENT?

    Wireless cable systems can carry any of the typical cable channels.  In
    the past, some channels refused to let wireless cable systems carry
    their signals.  However, the cable re-regulation bill made channels that
    are available to cable companies also available to wireless cable.  It
    can also send the 'SuperGuide' data along with similar data services.

5.0)  WHAT IS THE RANGE OF WIRELESS CABLE?

    Wireless cable systems optimally can get a range of up to 25-30 miles.
    This depends largely on the terrain, transmitting power, both the
    transmitting and receiving equipment, and many other factors.  In order
    to receive the signal, the transmitting and receiving antennas must be
    line-of-site.

    Because of its low startup costs, and the ability to reach places that
    cannot be served by traditional cable, MMDS may be feasible in certain
    rural areas.

    A range of 75 to 90 miles could be accomplished if a new digital
    compression system is used.  (See question 3.1)

5.1)  DOES WEATHER AFFECT RECEPTION?

    The answer to this question depends on the type of system used.  For
    systems that transmit their programming without modification (ie. No
    compression or scrambling), severe fog and/or rain can cause the signal
    to deteriorate.  From what I have heard, you can usually expect between
    eight to ten days per year of interrupted service.  This figure, I
    believe, is the average for the current systems operating in the U.S..

    If the programming is scrambled, the downconverter/descrambler may loose
    authorization sooner.

    On the other hand, if the programming is sent digitally, or is digitally
    compressed, the signal can deteriorate to a much lower level before the
    picture is affected.  However, once the signal gets this weak, the
    picture will deteriorate at a much faster rate as the weather gets
    worse.  From what I have read, the average number of days that this type
    of service would be interrupted, would be one day per year. (This sounds
    rather optimistic to me...does anyone have any info about this?)

    Also, the farther the receiver is from the transmitter, the sooner the
    picture will be affected.

6.0)  WHAT EQUIPMENT IS IN THE SUBSCRIBER'S HOME?

    Each household subscribing to the service has a small antenna on its
    roof (about the size of an open newspaper) and a downconverter inside.
    The downconverter usually includes an addressable decoder and a VHF/UHF
    tuner built in.  This gives it the ability to tune in broadcast channels
    without having to use up valuable MMDS channels.  It also allows
    pay-per-view services and simplifies channel blocking and premium
    channel activation/deactivation.

    Also, the subscriber will need a UHF and/or VHF antenna if they want to
    receive broadcast channels.

    Recently, a new converter has been introduced that will send _all_
    channels out of the converter at once.  This means that you can use
    your TV's and your VCR's built in tuner instead of having to have
    seperate boxes for each.  This new technology is (hopefully) going to
    be integrated into Wireless Cable converters as well as the traditional
    cable boxes sometime in 1994.

6.1)  IS WIRELESS CABLE EQUIPMENT RELIABLE?

    Several excellent manufacturers produce antennas and downconverters for
    signal reception along with decoder boxes.

    Because the signal is broadcast over the air, it is not subject to the
    failures of traditional cable.  However, the receiving end is somewhat
    more complex than most wired cable systems would use.  Also, the signal
    is in a frequency range that may be attenuated by water (such as rain)
    and can be blocked by trees.  There is also some risk of interference
    from microwave ovens operating in the area on 2,450 MHz.

    There are several companies that provide equipment and consulting
    services.  If you are interested in this, you may want to pick up the
    latest copy of The Broadcasting Yearbook or Multichannel News.  These
    can be found at most large libraries.

7.0)  WHAT ABOUT COPYRIGHT ISSUES?

    Currently, wireless cable systems have assumed that they may use a
    compulsory license to pay for copyright issues (similar to what cable
    companies do today).  A compulsory license enables systems to
    re-transmit broadcast signals for a pre-established fee to compensate
    producers of TV programs.  The copyright office recently announced that
    wireless cable is NOT a cable system,  therefore, these systems may not
    use compulsory licenses.  They have decided, though, that wireless cable
    systems may continue to use the compulsory license for two years (until
    December 31, 1994).  There is currently two bills that have been
    introduced that would extend this date.  One bill would extend the date
    to June 1, 1995 while the other bill extends it to June 1, 1997.  I will
    keep my eye out for this outcome.

8.0)  WHAT ABOUT SECURITY?

    In systems that use scrambling, signal security is provided by encoding
    each channel and equipping the converter with a decoding device that
    responds to a pilot signal carrying a data stream with authorization
    instructions.  Thus, the system is totally addressable.  No (legal)
    converter box will have any utility unless it is authorized for service
    by the central computer.  All channels, both Basic and Premium, are hard
    scrambled.  Because the wireless cable system is addressable, it can
    also accommodate pay-per-view service.

    One way to defeat this is to use an illegal converter box.  These are
    not as easy to find as the ones for regular cable systems.  However,
    a "Universal Descrambler" will probably be able to descramble the
    channels.  (I have not tried this).

    If digital compression is used, then no scrambling is needed as a
    compressed signal is impossible to watch.

    For more information on scrambling/descrambling, please refer to the
    "rec.video.cable-tv FYI List" posted in rec.video.cable-tv by Ed J.
    Gurney (egurney@vcd.hp.com).

9.0)  HOW ARE WIRELESS CABLE SYSTEMS REGULATED?

    The FCC has specifically preempted local regulation of wireless cable
    frequencies, asserting that it is interstate commerce.  There is no
    basis for local regulation of the wireless signal.  Unlike cable, no
    public rights of way are used, and all transmission and reception
    equipment is on private property.

    Furthermore, the antennas are so similar to regular television antennas
    that there can be no basis for zoning restrictions.  If a particular
    area does have zoning restrictions against antennas, they can be fought
    against in court (the newsgroup rec.video.satellite occasionally has
    these discussions).  However, if you signed an agreement that restricted
    antennas, you may be out of luck.

    If you find yourself in this situation, look at the "USENET Satellite
    FAQ List" posted in rec.video.satellite by Gary Bourgois.  Most of the
    information he provides about zoning restrictions applies to Wireless
    Cable antennas as well as TVRO (satellite) antennas.

10.0)  I SAW ONE OF THOSE 'INFOMERCIALS' ABOUT WIRELESS CABLE.  ARE THESE
       COMPANIES LEGIT?

    While some companies may be legit, there are some things that they don't
    disclose.  Because of this, two companies have had temporary restraining
    orders placed against them.  A judge has placed some of the following
    restrictions on them.

    1.  They may no longer state that applicants are "virtually guaranteed"
        of winning a license in the FCC lottery or that most wireless cable
        licenses are "highly valuable."

    2.  "There may be substantial delays in the awarding of any MMDS
        [Multichannel Multipoint Distribution System] license due to the
        length of time the FCC takes to process MMDS applications and award
        MMDS licenses."

    3.  That financing for wireless cable systems is hard to get, "given the
        relatively new nature of this field of technology and that such
        financing may require additional funds of the customer's own money
        as a condition" to obtaining system.

    4.  Provide a new "Risk Disclosure" statement that applicants must sign
        opinions and not actual values, that the winner of a MMDS lottery
        wins only 4 channels and that there may be competition with
        satellite, VCR, and other media.

    Temporary Restraining Orders have been placed on, or have been filed
    against: 1) Applied Telemedia Engineering and Management (A-TEAM) and
    2) Applied Cable Technologies (ACT).  If you deal with any type of
    application preparation firm, be very careful and read EVERYTHING.

    Other companies that MAY be questionable include Communications
    Engineering Management Services (CEMS), Decaxo Capital, Techno Source,
    and Western Wireless.  These companies have management that were
    involved in a company selling cellular licenses.  This company was
    forced out of business by the FCC for misleading customers.

    Other questionable companies include MMDS Technologies (also known as
    Metro Communications Group), Tele-Wave Technology, GMT Group (also
    known as National Micro Vision Systems), American Microtel Inc.  (a
    subsidiary of Halo Holdings Group which is affiliated with First
    Atlantic Equity Corp. and with Codima Inc.), Continental Wireless
    Cable Television, Spectrum Resources Group, Midas Media Inc, UEG L.C.,
    United Resource Group L.C., United Communications Ltd, and Application
    Resolution Trust (ART).  I have not heard anything about any other
    application preparation firm.

    MMDS Technologies (aka. Metro Communications Group) had a restraining
    order placed against them, but it was later removed.

    Applied Telemedia Engineering and Management recently lost a court
    battle and they must repay their customers $100,000 for falsely
    representing their product.  They also have to pay a $50,000
    Performance Bond.

    You may also want to be carefull if you invest in a Wireless Cable
    Company in Florida which is run by Key West Wireless Partners (KWWP),
    Gerald Wireless, and Satellite Microcable of Florida.  This company
    has been telling people that they are running a 32 channel system when
    they only have 12 channels.  They have not even applied for the other
    20 channels.

    Also, take note that in the U.S., it is ILLEGAL to enter into (or even
    plan on entering into) a settlement group when applying for a license.

    If you happen to see one of these commercials, I would appreciate it
    if you could write to me and give me their name and phone number so
    that I can get more information about different services.  Please also
    give me information on where you saw the ad.  I am currently trying to
    find out more about several other companies that are not listed above.

    For those of you who have written to me asking about different
    companies, please forgive me for how slow things are going.  I have
    been totally swamped with requests and it is very difficult to find
    out anything about some of these companies.  (They tend to enjoy
    calling themselves by many different names).  Investigations by both
    federal and state agencies are continuing on many companies, and these
    things tend to take a lot of time.  As I receive info, it will be
    placed here.

10.1  HOW CAN I TELL IF A COMPANY IS RUNNING A SCAM ON ME?

    The following article excerpt may help you.  It was taken from the Los
    Angeles Business Journal.  (Rackham, Anne "Beware of wireless cable
    scam, state warns public" April 20, 1992 v14 n16 pg 3(2)).
    (REPRINTED WITHOUT PERMISSION - Hoping to get it :-).

    --- BEGIN ARTICLE ---
    According to the Better Business Bureau and the Department of
    Corporations, the alleged scam works this way:

       * Investors are told that a wireless cable company is looking for
         investors who want to hold licenses for given areas that the
         company will service.

       * Each investor is asked to pay $5,000 to $7,000 and is told that
         the company will fill out and submit a license application in that
         person's name. The investor isn't told that the FCC filing fee is
         only $155.

       * The company submits several applications for one market, for which
         they've completed the required engineering studies, on behalf of
         numerous investors. These applications often don't meet the
         technical requirements to be successful.

       * Even if the investor wins a license, there may not be funding
         available to bring a system on line, or the business may not be
         profitable, much less return the outrageous sums mentioned in
         sales pitches.

    "Any time you hear someone say that they can turn $5,000 into a multi-
    million-dollar windfall, it's time to stop listening and hang up the
    phone," said Corporation Commissioner Thomas Sayles.
    --- END ARTICLE ---

11.0)  IS THERE AN INDUSTRY ASSOCIATION?

    Wireless cable operators, license holders, and equipment/service
    suppliers have formed the Wireless Cable Association.  Among its
    activities the WCA has established a set of industry standards, both
    business and technical.  The WCA has also made the industry's concerns
    known on Capitol Hill and at Federal agencies such as the FCC, NTIA,
    OTA and DOJ.  The WCA has also opened channels of communication with
    organizations such as the National League of Cities, NATOA, MPAA and
    the Association of State Attorneys General.

11.1)  WHO DO I CONTACT FOR MORE INFORMATION?

    FCC
    Common Carrier Bureau
    Washington, DC  20554
    (202) 634-1706

    Wireless Cable Association International, Inc.
    1155 Connecticut Avenue, N.W. Suite 700
    Washington, DC  20036
    (202) 452-7823
    FAX: (202) 452-0041

Disclaimer
----------

I have no affiliation with any type of cable or broadcast system.  I am
definitely not an expert in these areas.  I have tried, to the best of my
ability, to interpret and relay the most accurate and up to date
information.  However, I do not guarantee the accuracy of this information
as some of my sources may be biased or incorrect.

For additions, clarifications, corrections, or if you just have some
questions or comments, please feel free to e-mail me.

--
HACK/ER
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