This is a relatively easy modification that can be performed to most
TAPR TNC-2 boxes to allow 19.2K aynchronous communications between the
TNC and your computer.

FIRST ***  Replay U3 (LM324) with a TL084CN or TL094 FET op-amp.  The LM324
craps out at 9600 baud and is dead at 19.2K.

Cut the PC trace that goes to PIN 2 of U1 (divider) about 1/8 " from the
I.C. itself.  Solder a jumper from pin 10 of U1 to the trace that you
just isolated.  Solder to the side of the trace that goes to pin 1 and pin 6
of SW2 baud rate selector switch.

This supplies a 307.2 Khz clock (19.2K/16) to pin 1 which is now 19.2 K baud
on the serial port instead of 300 baud as well as pin 6 which is now 19.2 K
to the modem instead of 300 baud.  Turning on SW1 and SW7 will allow 19.2 K
baud on the serial port and 1200 baud on the radio port.

**** NOTE ****

The 19.2 K baud rate is UNRELIABLE with the PMS code.  We are using the
TAPR 1.1.6 code (or lower) without PMS and are having excellent results
on the serial port.  The radio port is currently running at 9.6 K and is
connected to a G3RUH modem and a Kantronics DVR 2-2.  Plans for next week
include increasing the G3RUH speed up to 19.2 K baud.

OHHHHH WHAT A FEELING.......

73 de VE3ZAV  Anthony Varga
              Kellogg Canada Inc
              London, Ontario, Canada
              519 455 9660  VMX 367