Comtech EF Data SMS-458B - Manual (Page 59)

SMS-458B Modem Protection Switch Revision 2
Operation MN/SMS458B.IOM
3–23
3.4.6.4 Battery Faults
The fault menu displays BATTERY fault when a battery failure occurs in the switch. The
message will be as follows:
M & C BATTERY FAULT
3.4.7 Front Panel Theory of Operation
The Front Panel Control module contains:
• 48-character, dual row LCD display
• 16-key
keypad
• 9
LEDs
• Audible
buzzer
• Peripheral logic to interface with the M&C module
The display, LEDs, and buzzer are mapped into address space of the external bus
structure. The display updates every second, and the LEDs and buzzer update as needed.
Any keypad activity provides an interrupt to the processor, which then scans the keypad.
After the input has been recognized, the processor takes the appropriate action.