Specifications

M&C and Interfaces SDM-309B Satellite Modem
4-4–16 MN/U-SDM309B Rev. #
RS-232 Specification
Circuit Supported RD, TD, DSR, RTS, CTS
Amplitude (RD, RTS) True: 14 V ± 11 V
False: -14 V ± 11 V
Amplitude (TD, DSR, CTS) True: 11 V ± 2 V
False: -11 V ± 2 V
Impedance
5000 ± 2000 ! <2500pF
Baud Rate Max: 1/2000 times the data rate
(Refer to Section 2.1.5 for details)
RS422 Specification
Circuit Supported SD, ST, TT, RD, RT, DM, RR, MC
Amplitude (RD,RT,ST,DM,RR)
4 ± 2 V differential into 100 !
Impedance (RD,RT,ST,DM,RR)
Less than 100 !, differential
Impedance (SD,TT,MC)
100 ± 20 !, differential
Polarity True when B positive wrt A
False when A positive wrt B
Phasing (RD,RT) False to True transition of RT nominally in center
of RD data bit.
Symmetry (ST,TT,RT) 50% ± 5%
Frequency Stability (ST) ± 100 ppm
V.35 Specification
Circuit Supported SD, SCT, SCTE, RD, SCR, DSR, RLSD, MC
Amplitude (RD,SCR,SCT,SD,SCTE)
.55 V pk ± 20% differential, into 100 !
Amplitude (CTS,DSR,RLSD)
10 ± 5 V into 5000 ± 2000 !
Impedance (RD,SCR,SCT)
100 ± 20 !, differential
Impedance (SD,SCTE)
100 ± 10 !, differential
Impedance (RTS)
5000 ± 2000 !, <2500 pf
DC Offset (RD,SCR,SCT) ± .6 V max, 1000 ohm termination to ground
Polarity (SD,SCT,SCTE,RD,SCR) True when B positive wrt A False when A
positive wrt B
Polarity (RTS,CTS,DSR,RLSD) True when <-3V wrt ground
False when >+3V wrt ground
Phasing (SCTE,SCR) False to True transition nominally in center of
data bit.
Symmetry (SCT,SCTE,SCR) 50% ± 5%
Frequency Stability (SCT) ± 100 ppm
G.703 Specification
Composite Data Rates Supported 1544 Kb/s 2048 Kb/s
Primary Data Circuits Supported T1 - SD,RD E1 - SD,RD
Interface Type Transformer Coupled Symmetrical Pair
Data Rate T1 - 1544 Kb/s ± 100 b/s
E1 - 2048 Kb/s ± 130 b/s
Pulse Width T1 - 324 ± 50 nsec
E1 - 244 ± 25 nsec
SD Amplitude
T1 - 3 +.3/- 1.5 V pk into 100 !
E1 - 3 +.3/- 1.5 V pk into 120 !
RD Amplitude
T1 - 3 ± .3 V pk into 100 !
E1 - 3 ± .3 V pk into 120 !
Pulse Mask T1 - G.703.2
E1 - G.703.6
Line Code Selectable AMI, B6ZS, B8ZS, or HDB3
Jitter Attenuation T1 - per AT&T 43802
T1 - per CCITT G.824
E1 - per CCITT G.823