Specifications

M&C and Interfaces SDM-309B Satellite Modem
4-4–4 MN/U-SDM309B Rev. #
4.1.2.2 Remote Baud Rate
The remote communications baud rate and parity is programmed by a switch pack (SP1)
on the M&C module. Programming the baud rate and parity is accomplished by setting
the switches. The switches are individually set in the OFF or ON positions. A switch is
programmed “OFF” by placing it in the position furthest away from the PCB (open).
“ON” is programmed by placing the switch in the position nearer the PCB.
Switch position #1 sets the parity as follows:
Even Parity- SP1-1 OFF
Odd Parity- SP1-1 ON
Switch positions #2, #3, and #4 set the baud rate as follows:
BAUD SP1-2 SP1-3 SP1-4
110 ON ON ON
150 ON ON OFF
300 ON OFF ON
600 ON OFF OFF
1200 OFF ON ON
2400 OFF ON OFF
4800 OFF OFF ON
9600 OFF OFF OFF
Note: SP1 on the M&C modules have four additional switches, (SP1-5 through SP1-8).
These four switch locations are not currently assigned or used.
4.1.2.3 Remote Address
Each modem must be configured for one address between 1 and 255 to communicate
using the established remote communications protocol. Each modem on a common
remote communications link (RS-485) must have a distinct address. Addresses are
programmed by a switch pack (SP2) on the M&C module. Addresses are binary coded
numbers set at SP2 with switch #1 (SP2-1) being the most significant bit and switch #8
(SP2-8) the least significant bit.
4.1.2.4 Battery
A rechargeable battery on the M&C module allows it to retain configuration information
without prime power for up to 30 days. A jumper JP6 is supplied on the M&C module to
disconnect battery power from the backup RAM. During normal operation this jumper
should be in the ON position. Should the Modem be powered down the following
sequence is carried out by the M&C microcontroller:
1. When power is applied to the M&C, the microcontroller checks the battery
backed up RAM to see if valid data has been retained. If valid data has been
retained the Modem is reconfigured to the configuration maintained in RAM.