Comtech EF Data C5 - Manual (Page 198)

Operation C5/K1/K3 Integrated Satellite Terminal System
4–72 Rev. 0
4.4.2 EIA-232, EIA-422, or V.35 Master/Slave
Refer to Figure 4-25 for:
! Clocking block diagram
! Transmit clock options
! Buffer clock options
! V.35 timing signals
! EIA-422 timing signals
The use of loop timing in the modem is an option for both EIA-422 and V.35 operation.
SCT (LOOP): SCT (INTERNAL) clock no longer applies when the modem has loop
timing on. The transmit clock source is now recovered from the receive satellite data.
This recovered clock is put out on the ST line and is used to clock the terrestrial
equipment. The transmit terrestrial clock is now essentially the same as the receive
satellite clock, except that it has been buffered by the terrestrial equipment. Select
transmit TERRESTRIAL for the transmit clock source when in loop timing. The SCT
(LOOP) indication serves as a reminder that the SCT internal clock is now the recovered
clock, not the internal oscillator. Select SCT (LOOP) when the terrestrial equipment does
not provide a transmit terrestrial clock.