Icom IC-2820H Instruction Manual page 141

D 1200 bps packet operation
q Connect the transceiver and a TNC as illustrated below.
q DATA IN
w GND
e PTT P
t AF OUT
w Set the TNC for transmit.
e Set transmit delay on the TNC to 50–100 msec., if avail-
able.
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.
TNC side
TX AUDIO
GND
y P SQL
RX AUDIO
PTT
SQL
OTHER FUNCTIONS
• Read the instructions supplied with your TNC carefully
before attempting packet operation with the transceiver.
• Pin t AF OUT is for 1200 bps operation only. This pin
cannot be used for 9600 bps operation.
• Over modulation may degrade signal quality. If you find
that many transmissions are failing, re-adjust the modu-
lation level.
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
120