Comtech EF Data SMS-458B - Manual (Page 63)

SMS-458B Modem Protection Switch Revision 2
Theory of Operation MN/SMS458B.IOM
4–3
4.1.2.2 Remote Baud Rate
The 8-position switch pack SP1 on the M&C module programs the external remote serial
communications baud rate and parity. Set the switches to ON (nearer the PCB) or OFF
(away from the PCB) to select parity and baud rate.
SP1 switch position 1 (SP1-1) sets the parity:
• OFF = even parity
• ON = odd parity
SP1 switch positions 2, 3, and 4 (SP1-2, SP1-3, and SP1-4) 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
4.1.2.3 Remote Address
The switch connects to an EIA- 485 remote communication link. To communicate on this
link, each switch and modem must have a unique address between 1 and 255.
Note: “0” cannot be a device address, as it is the global address for all devices.
To program an address, use the 8-position switch pack, SP2, on the M&C module.
Addresses are binary coded numbers:
• Switch position 1 (SP2-1) is the most significant bit.
• Switch position 8 (SP2-8) is the least significant bit.