Comtech EF Data MIDAS Version 4.X NMS Configuration - Manual (Page 51)

MIDAS 4.X NMS Configuration, Rev.6
Setup and Operation 2–23
The inbound control channel characteristics are summarized as follows:
• Pre-assigned digital SCPC channel using TDMA.
• Transmission is burst mode at 19.2 kbps, QPSK, FEC1/2.
• Only one inbound control channel is supported.
• Messages on the inbound control channel are contained in an HDLC
frame.
• The nodes trigger the transmit off the trailing edge of the NMS
outbound transmissions.
• As the inbound control channel operates in a contention mode, the
node waits for an HDLC level acknowledgment from the NMS on the
outbound control channel. A lack of acknowledgment leads to
message re-transmission after a random backoff.
From the MIDAS window, click Configuration Management, highlight System
Administration, and then select the Control Channel’s tab to display the Control Channel
window. This window allows the operator to set the following Control Channel
parameters.