Comtech EF Data SMS-758 - Manual (Page 81)

SMS-758 Modem Protection Switch Theory of Operation
MN/SMS758 Rev. 3 4–21
4.6.3.1 Electrical Specifications
V.35
Circuit Supported SD, SCT, SCTE, RD, SCR, DSR, DSR, RLSD
Switching Format Modulator and demodulator signals individually
with dry contacts
Contact Arrangement Mod Signals: 8 poles
Demod Signals: 8 poles
Amplitude (RD, SCR, SCT, SD, SCTE) 0.55V peak ± 20 % differential into 100 Ω
Amplitude (CTS, DSR, RLSD) 10 ± 5V into 5000
±
2000 Ω
Impedance (RD, SCR, SCT) 100 ± 20 Ω
Impedance (SD, SCTE) 100 ± 10 Ω
Impedance (RTS) 5000 ± 2000 Ω ,
<
2500 pF
DC Offset (RD, SCR, SCT) ± 0.6V max., 1000 Ω termination to ground
Polarity (SD, SCT, SCTE, RD, SCR) True when B positive wrt A
False when A positive wrt B
Polarity (RTS, SCT, DSR, RLSD) True when
<
-3V wrt GND
False when
>
+3V wrt GND
Phasing (SCTE, SCR) False-to-true transition, nominally in center of data
bit
Symmetry (SCR, SCTE, SCT) 50
%
, ± 5
%
Frequency ± 100 PPM