Model Builder supports several types of Watchdog Timer signals via the parallel port. The table below lists the corresponding parallel port bit number, the watchdog timer signal description, and the Model Builder version where the signal was first implemented.

Care should be taken when interfacing to the DACS parallel port as improper interface could cause parallel poert of possibly CPU failure.

			Active
PIN	BIT	FUNCTION	Toggle	High	MB Version
2	0	Model Builder (MB) Running	X		3.03+
3	1	Model Builder running w/no errors	X
4	2	Model Builder running w/no errors		X	3.03+
5	3	MB running; DSPs running OK	X		3.03+
6	4	DSPs not muted		X	3.04+
7	5	MB running; main Rx packet from host active	X		3.03+
8	6	No system errors		X	3.04+

PIN	Description	I/O
1	-Strobe	Out
2	+Data Bit 0	Out
3	+Data Bit 1	Out
4	+Data Bit 2	Out
5	+Data Bit 3	Out
6	+Data Bit 4	Out
7	+Data Bit 5	Out
8	+Data Bit 6	Out
9	+Data Bit 7	Out
10	-Acknowledge	Out
11	+Busy	In
12	+Paper End	In
13	+Select	In
14	-Auto Feed	Out
15	-Error	In
16	-Initialize Printer	Out
17	-Select Input	Out
18	-Data Bit 0 Return (GND)	In
19	-Data Bit 1 Return (GND)	In
20	-Data Bit 2 Return (GND)	In
21	-Data Bit 3 Return (GND)	In
22	-Data Bit 4 Return (GND)	In
23	-Data Bit 5 Return (GND)	In
24	-Data Bit 6 Return (GND)	In
25	-Data Bit 7 Return (GND)	In