Comtech EF Data SMS-301 - Manual (Page 114)

SDM-2020 System Installation SMS-301 Redundancy Switch
C–12 Rev. 3
C.1.5 Connect to SDM-2020 Satellite Modulator I/O Connector,
25-Pin Interface
Note: The section defines the requirements of the I/O 25-pin data interface for video and
high-speed data applications used with the SDM-2020 Satellite Modulator. This interface
uses serial format only.
C.1.5.1 Description
The SMS-301 data interface is a plug-in module that interfaces with the SDM-2020
Satellite Modulator. The interface used EIA-530 serial format
Refer to Table C-6 for the cable pin assignments.
Table C-6. Pin Assignments, 25-Pin
SMS-301 DB25 Connector SDM-2020 EIA-530
Pin # Name Serial (J4) DB 25
24
11 TT-A
TT-B 24
11 TT-A
TT-B
2
14
SD-A
SD-B 2
14
SD-A
SD-B
1 SG 1 SG
15
12 ST-A
ST-B 15
12 ST-A
ST-B
21 DF 21 DF
25 MF 25 MF
C.1.5.2 Connect to SDM-2020 Modulator with I/O Connector, 25-Pin
Interface
Refer to Figure C-5.
1. Connect the “COMM” data interface connector (J1) to the DTE equipment.
Note: Equivalent cable shall be computer grade, 100
Ω, incorporating twisted and
shielded pairs. Typical length shall be
≤ 16 feet (5 meters).
2. Connect the “A” data interface connector (J2) to the prime SDM-2020 Modulator
“SERIAL” (J4) connector using Cable (CA/3588) or equivalent.
3. Connect the “B” data interface connector (J3) to the backup SDM-2020
Modulator “SERIAL” (J4) connector using Cable (CA/3588) or equivalent