Vertex Standard FT-2800M User Manual

The FT-2800M may be used for 1200 bps Packet operation, using most all commonly-
available Terminal Node Controllers (TNCs). Connections between the transceiver and the
TNC are accomplished via the front panel Microphone connector and rear panel External
Speaker jack, per the diagram below.

The audio level from the receiver to the TNC may be adjusted by using the VOL knob, as
with voice operation. The input level to the FT-2800M from the TNC should be adjusted at
the TNC side; the optimum input voltage is approximately 4 mV at 2000 Ohms.

Setting of the optimum TX Audio level: first, connect the MH-48

 to the Microphone

connector, and while listening on a monitor receiver, transmit on the FT-2800M and press
one or more of the Microphone’s DTMF keys. Note the audio level of the DTMF tones
heard in the monitor receiver, then, after removing the microphone and hooking up the TNC,
set the TX Data level “by ear” to about the same level. In most cases, this level of accuracy
in adjustment will be sufficient for good throughput.

Be sure to turn the transceiver and TNC off before connecting the cables, so as to prevent
voltage spikes from possibly damaging your transceiver.