Icom IC-2820H Instruction Manual page 141

D DATA JACK PIN ASSIGNMENT
q
e
t
q DATA IN
Input terminal for data transmit. See p. ?? for details on
how to toggle data speed between 1200
9600 bps
(G3RUH, GMSK)
w GND
Common ground for DATA IN, DATA OUT and AF OUT.
e PTT P
PTT terminal for packet operation only. Connect ground to
transmit data.
r DATA OUT
Data out terminal for 9600 bps operation only.
t AF OUT
Data out terminal for 1200 bps operation only.
y P SQL
Becomes high (+5 V) when the transceiver receives a sig-
nal which opens the squelch.
• To avoid unnecessary TNC transmission, connect squelch to the
TNC to inhibit transmission when receiving signals.
• Keep audio output at a normal level, otherwise a "P SQL" signal
will not be output.
D 1200 bps packet operation
w
r
Front panel view
y
(AFSK)
.
q Connect the transceiver and a TNC as illustrated below.
q DATA IN
e PTT P
and
w Set the TNC for transmit.
e Set transmit delay on the TNC to 30–50.
r Adjust the TNC frequency deviation if necessary.
• When using a deviation meter:
Adjust the output of the TNC so that frequency deviation
is in the range ± 3 to ±4 kHz.
• When NOT using a deviation meter:
A receiver or transceiver is needed to monitor the trans-
mission—compare the received audio output level when
receiving a TNC modulated signal with high level voice
signals using the microphone. Then adjust the TNC mod-
ulated signal to a lower level than the voice modulated
signal.
OTHER FUNCTIONS
TNC side
TX AUDIO
GND
w GND
y P SQL
RX AUDIO
t AF OUT
PTT
SQL
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