Operating instructions

October 20, 1998
Switch Control 19
Figure 15:
Parallel Port Line Assignments
The following BASIC program can be used to control the VX500 from a PC printer port. The
program switches channel-by-channel from channel 1 through channel 8. If an error is
encountered, the program resets the switch. If the error persists, the program exits. The
program expects the VX500 to be connected to the printer port as outlined in Figure 15.
Depending on the speed of your PC, you may have to insert a delay after the STROBE low
commands (lines 90, 150) in order to satisfy minimum pulse width constraints.
GND 1
GND 2
D0 3
D1 4
D2 4
D3 6
D4 7
STROBE 8
BUSY 9
ERROR 10
RESET 11
POWER 12
1 -STROBE
2 DATA BIT 0
3 DATA BIT 1
4 DATA BIT 2
5 DATA BIT 3
6 DATA BIT 4
7 DATA BIT 5
8 DATA BIT 6
9 DATA BIT 7
10 -ACK
11 BUSY
12 PE
13 SLCT
14 -AUTO FEED
15 -ERROR
16 -INIT
17 -SLCT IN
18 GND
19-25 GND
–
+
VX500 SWITCH
PARALLEL PORT
POWER SUPPLY