Rear Panel - Yaesu FT-991A Operating Manual

1 2
3 4
GND
Use this terminal to connect the transceiver to a good
earth ground, for safety and optimum performance.
Use a large diameter, short braided cable to make
the ground connections. For details on grounding the
transceiver, see "Grounding" on page 14.
ANT Jack ( 144/430MHz )
This is the M-type (European version: N-type) co-
axial connector for the 144 MHz band and 430 MHz
band antennas ( 50 ohms ) .
RTTY/DATA Jack
This is the input/output jack to connect a terminal
unit for RTTY and TNC for packet communications.
① ②
③ ④
⑤ ⑥
TUN/LIN Jack
Connect the optional external antenna tuner "FC-40"
or the linear amplifier "VL-1000".

 
 
 

F T-991 Operating Manual
6
5 7
① DATA IN
② GND
③ PTT
④ SHIFT
⑤ DATA OUT
⑥ SQL
+13V OUT

TX GND

GND

TX D (BAND A)

RX D (BAND B)

BAND C

RESET (BAND D)

TX INH


Rear Panel

10
8 9
GPS/CAT Jack
This is the RS-232C jack for connecting a computer
or a commercially available external GPS device.
Connecting a computer to this jack, using a com-
mercially available RS-232C straight cable, enables
CAT control of the transceiver.
⑨ ⑧ ⑦ ⑥
⑤ ④ ③ ② ①
DC IN Jack
This is the DC power supply connection for the
transceiver. Use the supplied DC cable to connect di-
rectly to a DC power supply, which must be capable
of supplying at least 23 A @13.8 VDC.
11
① DCD
② SERIAL OUT/RXD
（GPS DATA IN）
③ SERIAL IN
④ DTR
⑤ GND
⑥ DSR
⑦ RTS
⑧ CTS
⑨ RI
Page 27