MOBILE MAP PLUS SYSTEM WITH MICROCONTROLLER OPERATION
DESIGN CRITERIA

September 27, 1993

ENCODER

	INPUT SCAN

	64 input same as current system
	Provide shorting jumpers for alarm input power like RANS board.

ALARM CODING

Send FSK preamble for lock.
Send alarm message twice.
Send parity check.
Send watchdog signal every five minutes (as current system).
Send watchdog signal only - no alarm signals.

OUTPUTS

600 ohm transformer with keying signal (same as now) - screw terminals.
Low impedence output, no keying (for Motorola interface).
To DB 15 on circuit board.
Auxiliary input and output for future tone signalling.
Separate keying output for Motorola - to DB 15.
Test output (no keying for testing mobile display - to DB 15)
Can we have jumper to show when test map is connected?
Ok to send input from Motorola - on DB 15 
( “0” = OK to send, 0 voltz).
Request to send output for Motorola - on DB 15.
(“1” = +3 volts, “0” = 0 volts)
Time out after x seconds and send signal anyway.

DIAGNOSTIC LAMPS AND CONTROLS

Pot for setting deviation (output level) on encoder board.
Diagnostic lamps: 
Power on
Request to send
Clear to send
Sending alarm

POWER SUPPLY

Same as current system.
Provide battery plug and screw terminals like RANS board.

TEST FUNCTIONS

Two test conditions possible:

1. 	Press test button for normal send of alarms.
	For Motorola watch diagnostic lamps.

2.	When testing mobile displays plugged into encoder board.
Provide jumper on DB 15 to send input signal only.

MOBILE DISPLAY - DECODER

INPUT SIGNAL

Same as now - input from radio.
Capacitor coupled (for Motorola).

ALARM CODING

Look for FSK lock.
Receive two transmissions.
Compare parity.
Compare two transmissions.
If valid signal, illuminate alarm lamps.
Watchdog every 7 minutes as current system.

DIAGNOSTIC LAMPS

INT - interference (radio modules only)
FSK LOCK - all models
VALID ALARM - all models
WATCHDOG LAMP, with timeout as current system.

TEST FUNCTIONS

Lamp test same as current system.
System test - sequentially generate alarm signals to illuminate each alarm lamp.

LAMP DRIVERS

Output matrix, if possible.
Wire for DIP plugs to match current lamp wiring.
Red lamps flash and audible sounds (same as now).
Green lamps solid on (same as now).

AUDIBLE ALARM

Same as current system.
Put plug on board for remote audible mounting.

HORN RELAY

Same as current system.