1-27-95                  Zoom/Modems- specs/settings

                            Don Hinds - Tech Support

     There  are  too many models, present and past of Zoom modems  to  list
each  individually. They fall into two basic groups. V-series with  V42bis,
(both  2400  and  V32(bis) models), and plain  2400  modems (some with 
RPI).  All  V-series Zoom  Faxmodems use both Class 1 & Class 2 FAX. Non-V- 
series modems may  be either.  Zoom/modems support (depending on model) the 
following  standards: CCITT - V32(bis), V42(bis), V22(bis), V21, & Bell - 
103, 212A.

     The  plain  2400 (and RPI) modems are Hayes Smartmodem compatible.  
The  factory defaults  are  like  Hayes, including &C0 &D0. All  Hayes  
Smartmodem  2400 settings and AT commands should work. Our recommended INIT 
string for  most PC applications is AT&F&C1&D2, Mac AT&F&C1&D0. Use 
XON/XOFF flow.

     The   V-series   and   Hi-speed   RPI   modems   include    2400v42bis
data/faxmodem/voice modems, and v32(bis) 9600+ modems. Factory defaults are
the  same  as  the  2400  modems,  plus  (*autoreliable)  *v42bis  protocol
negotiation = ON (*&Q5), RTS/CTS = ON (&K3). The recommended INIT string is
the same as the 2400 plain modems. Two exceptions: The 'large white' v42bis
modem  and  the v32 Turbo modem, add S36=7 to the string  (default  in  all
other V-series Zoom modems). We recommend using &Q6 to turn v42bis protocol
OFF,  and *&Q5 to turn it ON. In some cases (direct mode) &Q0  may  replace
&Q6.  RTS/CTS  flow  &K3 = ON, &K4 = XON/XOFF, &K0  =  none.  Set  software
Autobaud =OFF, follow connect =OFF. Set v32 modems to 19,200 or 38,400, and
2400  v42bis  modems  to  9600 in the software.  Default  the  modem  gives
computer-modem connect messages so modem keeps one fixed speed (as long  as
you do NOT use the Wx or S95=x command).

     I  would  say for almost all applications you can  devide  Zoom/modems
into  two groups. Plain 2400 Zoom, and Zoom V-series modems.  Just  include
the S36=7 for the V-series, (AT&F&C1&D2S36=7) and it will set the only  two
that  are  not that way by default, and don't affect the others,  which  do
have that default.

     For  PCs  you  use  a  straight  through  cable.  MACs  should  use  a
'Universal' cable. Some 'odd' system may require a null-cable.

(* not applicable to RPI modems. Software does V42(bis)/MNP)

If you need specific commands/registers please fax me a  list.

                                   Don Hinds - Zoom Tech
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