9600 FULLDUPLEX on the Pac-Comm TNC-220
by D. Hulatt G4WFQ 19th Aug 90
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Locate 74HC4020 and remove from IC socket
CAREFULLY bend pins 1 and 12 up
Solder flying leads to pins 1 and 12 on 74HC4020
Solder flying lead to pin 12 on SIO 8530 chip
Use a SPDT switch to switch to 2 signals from 4020 to SIO
Replace 4020
Drill 1/4 inch hole in rear plate above RS232 slot
Insert switch and secure.
Thats it. Throw switch for 9600 FULLDUPLEX operation, revert for
normal. NB: You still have to change buad rate in s/w.
I hope this information will be of use to some. I would like to thank
Uk Agent for trying to get info from Pac-Comm. It must be like trying to
get blood out of a stone.
Thanks Pac-Comm, no need to bother now I've done it myself!
