Comtech EF Data DMD1050TS, Installation And Operation Manual

Page: 67 / 316

DMD1050TS Satellite Modem Board
Revision 1
Theory of Operation 3–35 MN-DMD1050TS
3.17.5 SCC Overhead Channel Setup
1. Set the Framing Mode (located under Mod and Demod Data Menus) to SCC.
After doing this, two new menus show to the right of the Framing Menu, for both the Mod
and Demodulator:
SCC CTL RATIO
SCC INBAND RATE
2. Set the desired SCC control ratio:
SCC CTL RATIO {1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7}
This allows you to simulate the framing used by the Satellite Control Channel Option
(Pass-Thru Mode only). The SCC CTL RATIO is the ratio of overhead in-band data to
synchronizing words.
3. Set the desired SCC in-band rate:
SCC INBAND RATE {300 to 115200}
This allows you to request the rate of in-band data for the overhead channel. This sets
the overhead amount only. The actual amount of data that can be passed through the
overhead channel will be set under ES Baud Rate.
4. Go to Interface > General > Tx ASYNC MODE.
5. Set the desired ES Interface type:
ES INTERFACE {RS-232, RS-485}
This allows you to select the interface type.
6. Set the desired baud rate for the ASYNC Port (J1).
This will be the baud rate that will pass through the overhead channel:
ES BAUD RATE {150 - 115200}
This allows you to select the baud rate of the ASYNC port (J1) in SCC Mode.
7. Set the desired ES BITS/CHAR:
ES BITS/CHAR {7,8}
This allows you to choose between 7 or 8 bits of data.
8. Go to Interface > General > Rx ASYNC MODE and repeat Steps 5 through 7.
The physical connection to the overhead channel is a 10 pin dual row male header (J1). See
Appendix E for mating connector details.