Comtech EF Data SDM-309B - Manual (Page 83)

M&C and Interfaces SDM-309B Satellite Modem
4-4–6 MN/U-SDM309B Rev. #
INTF_LBk Interface Loop Back [OFF]
Coding [AMI]
TX_2047 [OFF]
TXD_Flt [NONE]
RXD_Flt [NONE]
Buf_Size [384]
Read_ERR [FRAME]
Dscrmblr Descrambler [ON]
Scramblr Scrambler [ON]
4.1.2.8 Utility Defaults
POW ADJ Power Adjust [-5.0 dBm]
OP MODE Operation Mode [Duplex]
Fast_ACQ Fast Acquisition [OFF]
Note: If Battery backed RAM fails the valid data test time and date are set as follows:
Date 7/4/76
Time 12:00AM
4.1.3 Remote Interface Specification
Refer to Appendix B for the remote interface specification.
4.1.4 Monitor and Control Theory of Operation
The Monitor and Control module is built around the Intel 80C31 microcontroller
operating at 5.5295 MHz. The microsystem is designed to support 64K bytes of read
only code memory and 64K bytes of random access data memory. Of the 64K bytes data
memory only 4K is used for RAM, the remaining address is used for memory mapped
I/O. Memory mapped I/O includes real time clock/memory, a eight channel analog to
digital converter and external buffered bus structure for overall modem control and status
gathering. The 80C31 microcontroller supports a serial asynchronous communications
channel with a maximum baud rate of 9600bps using the 5.5295 MHz reference. A
rechargeable battery is employed to maintain the system real time clock and modem
configuration through power out situations.
4.2 Digital Interfaces