Comtech EF Data SDM-300A - Manual (Page 384)

SDM-300A Satellite Modem Revision 6
Specifications MN/SDM300A.IOM
19–28
The following interface types are available through the optional 50-pin data I/O connector
with overhead card installed. In order to meet the mechanical specification, the correct break
out panel must be connected to the modem.
• G.703
• IDR
• IBS
• Drop and Insert (G.703)
19.9.2 EIA-232 Specification
EIA-232 Specification
Circuit Supported
TXD, TXC, ST, RXD, RXC, DSR, DCD, CTS, LL, RTS, MC
Driver Amplitude (RXD, RXC,
ST, CTS, DM, DSR)
True: 10V, ± 5V
False: -10V, ± 5V
Receiver Amplitude (TXD,
TXC, RTS, LL, MC)
True: Minimum +1V
False: Maximum -1V
Impedance 5000, ± 2000Ω < 2500 pF
Data Rate 9.6 to 120 kbps
Circuit Assignments
TXD Send Data
RXD Receive Data
RTS Request to Send
CTS Clear to Send
DM Data Mode
DSR Receiver Ready
MC Master Clock
LL Local Loopback
ST Send Timing
RXC Receive Timing
TXC Terminal Timing
MF Mod Fault (ttl)
DF Demod Fault (ttl)