3-8-95                           
AC HUM


Though it's rare, you can get an AC hum when hooking devices together. 
Try reversing one of the plugs in the AC outlet.  If that doesn't do fix 
it, the cause may be RF ('radio freqency' inerference) from some nearby 
electric device.

                 RF....

The  phone wire or cable is acting as an antenna. Make sure the internal  
modem is  screwed  down to the computer case or the cable is screwed in  at  
both plugs. Some motherboards are not grounded (held by clips instead of 
screws) and they should be grounded. 

Try  some  tinfoil around the phone wire, and the wire  should  be  as 
short  as  possible.  Slide the foil up/down the wire to de-tune  it.  This 
usually works, unless the house wiring is picking it up. then you may  need 
a phone filter (from Radio Shack etc.).

We  had  a new cause of interference today. Someone had a  modem  near some 
kind of a 'cable box'. When he moved it, the problem was eliminated.


                                   Don Hinds - Zoom Tech

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