Specifications

SDM-309B Satellite Modem M&C and Interfaces
MN/U-SDM309B Rev. # 4-4–21
The engineering service channel is provided on a 25 pin “D” female connector assessable
from the front panel of the breakout panel. Screw locks are provided for mechanical
security of the mating connector.
Signal Function Name Pin Number
GROUND GND 1, 7
TRANSMIT DATA TXD 2
RECEIVE DATA RXD 3
REQUEST TO
SEND/CLEAR TO SEND
RTS/CTS 4
5
TERRESTRIAL ESC DATA
SET READY
TER_ESC_DSR 6
Note: RTS and CTS are looped together on the connector.
4.2.1.9.5 G.703 Interface (J5)
The G.703 interface is provided on a 15 pin female "D" connector and is located on the
front of the break-out panel. Screw locks are provided for mechanical security of the
mating connector.
Signal Function Name Pin Number
GROUND GND 2, 4
RECEIVE DATA T1E1_RD-A
T1E1_RD-B
3
11
SEND DATA T1E1_SD-A
T1E1_SD-B
1
9
EXTERNAL CLOCK EXC-A
EXC-B
7
8
4.2.1.9.6 External Reference Clock (J6)
This connector is the interface for the unbalanced external reference clock input. To
activate this connector, SW1 must be in the UNBAL position. If the balanced external
reference clock input is to be used SW1, must be in the BAL position. Switch 1 is
located on the front panel to the right of the external reference clock input.
4.2.1.9.7 Send Data (J7)
This connector is the interface for the unbalanced Send Data input. To activate this
connector SW2 must be in the UNBAL position. If the balanced Send Data input is to be
used, SW2 must be in the BAL position. Switch 2 is located on the front panel to the
right of the send data input.