Yaesu FT-901DM Maintenance Service Manual page 15

GENERAL
REAR APRON CONNECTIONS
(1) GND
Threaded lug for ground connection.
(2) RF OUT
Signal frequency output from the driver stage
may be obtained at this jack for use with optional
equipment, such as the FTV-90IR VHF/UHF
transverter.
(3) ANT
Coaxial connection for antenna.
(4) PO ADS
Sets PO meter sensitivity
(5) RCV ANT
A second receiver receives its antenna connection
through this jack.
(6) ACC
Accessory socket. Provides access to transceiver
Operating voltages and relay contacts.
(7) KEY
Three-conductor jack for connection to keyer
paddle or external key.
(8) EXT VFO
Connections for external VFO.
1-10
(9) FUSE
Fuse holder requires 5 amp fuse for 117 volt or
3 amp fuse for 220 volt operation. For 12 volt
DC operation, a 20 amp fuse is installed in the
power cable. When replacing fuses, be certain to
install a fuse of the proper rating. The warranty
does not cover damage caused by improper fuse
replacement.
(10) POWER
Power receptacle. Both AC and DC cables are
supplied
(11) TONE
Sidetone output for second receiver (if used).
(12) IF OUT 2
Wide-bandwidth 8.9 MHz IF
to a spectrum analyzer, etc.
al for connection
(13) PATCH
Speech input terminal for phone patch connection.
Impedance is 500 ohms.
(14) A-TRIP
Anti-trip input from second receiver (if used).
(15) SP
Audio output is provided at this jack for an ex-
ternal speaker. Output impedance is 4 ohms, and