Comtech EF Data SLM-7650 Installation And Operation Manual page 103

SLM-7650 Satellite Modem
Theory of Operation
4.4.3.2.1.7 IBS Overhead ESC
The interface option card provides access to the IBS engineering service channels at the
50 pin connector. IBS ESC requirements are defined within IESS-309 and IESS-403.
Characteristic
IBS Octet Signaling
IBS Backward Alarm
Prompt Alarm Indication
Service Alarm Indication
ESC Data Channel
ESC TX Data Channel
ESC RX Data Channel
Definitions
Provides support for octet (byte) alignment signaling for the
primary data channel. The octet signal is active for one clock
period, framing bit 0 of an 8 bit data sequence. The receive
side octet signal is provided as an output every eighth bit.
The transmit side octet signal is an input that is used to
synchronize the octet to the IBS multi-frame.
IESS-309 compatible
Form C Relay, contacts accessible through the 50 pin
connector
Form C Relay, contacts accessible through the 50 pin
connector
EIA-232 interface accessible through the 50 pin connector.
Refer to IESS-309 and IESS-403.
ESC TX data is sampled on the rising edge of the ESC TX
clock sourced from the overhead card. The ESC TX clock
will have a period of 1/480 of the transmit terrestrial data rate
and a duty cycle of approximately 50%.
ESC RX data and clock is sourced from the overhead card.
Data transitions occur on the falling edge of the clock. The
clock period will be 1/480 of the receive terrestrial data rate
and have a duty cycle of approximately 50%
4–21
Revision 4
MN/SLM7650.IOM