37
4
RECEIVE AND TRANSMIT
■
Packet operation
D
Connections for packet
Rear panel
DATA
PTT
PTTP
DATA IN
SQL
RX AUDIO
GND
TX AUDIO
TNC SIDE
TU or TNC
RS-232C
Personal computer
q
w
e
y
t
r
AF OUT
DATA OUT
GND
SQ
q
w
e
y
t
r
PIN #/NAME
DESCRIPTION
q
DATA IN
Communication data input.
w
GND
Ground for DATA IN, DATA OUT and AF OUT.
e
PTTP
Transmits when grounded.
r
DATA OUT
Outputs 9600 bps receive data.
t
AF OUT
Outputs 1200 bps receive data.
y
SQ
Squelch output.
Goes to ground when squelch opens.
Rear panel view
D
Adjusting the transmit signal output from the TNC
☞
NOTE:
For packet operation the transceiver can
be set to one of two data speeds: 1200 bps or
9600 bps. Data speed is set in initial set mode
(see p. 54 item 29
9600 MODE
).
Data speed is set in initial set mode (see p. 53 item
29
9600 MODE
).When setting data transmission
speed to 9600 bps, the
DATA
signal coming from the
TNC is applied exclusively to the internal limiter cir-
cuitry to automatically maintain bandwidth.
NEVER apply data levels from the TNC of over 0.6
Vp-p, otherwise the transceiver will not be able to
maintain the band width and may possibly interfere
with other stations.
☞
NOTE:
Read the instructions supplied with your
TNC carefully before attempting packet operation
with the IC-706MKIIG.
1. When using a level meter or synchroscope, adjust
the TX audio level (
DATA IN
level) from the TNC as
follows.
0.4 Vp-p (0.2 Vrms): recommended level
0.2 Vp-p–0.5 Vp-p (0.1 Vrms–0.25 Vrms):
acceptable level
2. When not using a measuring device.
➀
Connect the IC-706MKIIG to a TNC.
➁
Enter a test mode (“CAL”, etc.) on the TNC, then
transmit some test data.
➂
When the transceiver fails to transmit test data or
transmits sporadically (TX indicator doesn’t appear
or flashes):
Decrease the TNC output level until the transmit
indicator lights continuously.
When transmission is not successful even though
the TX indictor lights continuously:
Increase the TNC output level.
D
Data socket
