4: Technical Description
4-6
MT1099A-MS
Figure 4-4. Tuner Control Connector J3 Pinout
Pin
Signal
Description
A
Key
Return key signal from antenna tuner.
Keys the transceiver into low-level
carrier tune power.
B
+12 Vdc
Switched (12 Vdc) line external antenna
tuner.
C
Ground
Chassis ground.
D
Tune Initiate
Tune initiate signal from transceiver. A
momentary ground from the transceiver
that initiates a tune cycle in the antenna
tuner.
E
ATU TX
Serial data (channel number) from
transceiver to the antenna tuner.
F
ATU RX
Check tune, negative-going pulse from
the transceiver that causes the tuner to
read memory and tune according to
settings stored in memory.
G
RS232 RXD
Clock: toggles to latch data in tuner so
that it can be read. Not used on
RAT7000B.
H
RS232 TXD
Strobe: a high level on this line allows the
tuner to load to BCD channel parallel
data into the serial-out shift register. Not
used on RAT7000B.
J
SW DC OUT
Switched DC (+12 or 24 Vdc) primary
power out to the antenna tuner. Not used
on RAT7000B.
N
N/C
No connection.
A
B
C
D
E
F
G
H
J
K
