Specifications

SDM-100A Satellite Modem Theory of Operation
Rev. 0 4–21
4.4.2.1 Connector Pinouts
The V.35 interface is provided on the industry standard 34-pin block or 25-pin D
connector accessible from the rear panel of the modem. Screw locks are provided for
mechanical security of the mating connector.
Signal Function Name 34-Pin Block
Pin #
25-Pin ‘D’
Pin #
Send Data SD-A P 2
SD-B S 14
Serial Clock Transmit SCT-A Y 15
SCT-B a (AA) 12
Receive Data RD-A R 3
RD-B T 16
Serial Clock Receive SCR-A V 17
SCR-B X 9
Serial Clock Transmit External SCTE-A U 24
SCTE-B W 11
Master Clock (Input) MC-A c (CC) 20
MC-B d (DD) 23
Request To Send RTS C (See note) 4
Clear To Send CTS D (See note ) 5
Data Set Ready DSR E 6
Receive Line Signal Detect RLSD F 8
Modulator Fault --- m (MM) 25
Demodulator Fault --- n (NN) 21
Shield Shield 1
Signal Ground SG A, B 7
Note: The Request to Send (RTS) line is hard-wired to the Clear to Send (CTS) line
by JP11, pins 5 and 6, on the Demodulator/M&C card (AS/4379), since the modem
does not support polled operation.