Comtech EF Data SDM-300L3 - Manual (Page 301)

12–1
Chapter 12. G.703
12.1 G.703
G.703 data is either in AMI, B8ZS (8 zero) suppression, or HDB3 (3 zero) suppression
formats. There is not a coexisting clock that is on a separate line for G.703 data. The
clock is derived from the data stream within the modem and in the user equipment. Loop
timing, if desired, must occur in the customer equipment for the link to operate in
Master/Slave. The modem cannot do loop timing in G.703 operation because the modem
does not emit an ST signal for the Transmit Clock Source.
12.1.1 G.703 Specifications
Table 12-1. G.703 Specifications
Parameter Specification
Primary Data Circuits Supported T1 SD, RD
E1 SD, RD
Interface Type Transformer coupled symmetrical pair
Data Rates T1 1544 kbps ± 100 bps
E1 2048 kbps ± 130 bps
Pulse Width T1 324 ± 50 Ns
E1 244 ± 25 Ns
SD Amplitude T1 3V +0.3/-1.5V-pk into 100 Ω
E1 3V +0.3/-1.5V-pk into 120 Ω
RD Amplitude T1 3V +0.3/-1.5V-pk into 100 Ω
E1 3V +0.3/-1.5V-pk into 120 Ω
Pulse Mask T1 G.703.2
E1 G.703. 6
Jitter Attenuation T1 G.824
E1 G.823
Line Code AMI, B8ZS, B6ZS, HDB3