Programming the User Defined Character

The turn off string also adds the ASCII ESC character to the front of the three-character turn off string.

The first character is the ASCII ESC character. The second and third character of the command control string is the user-defined character. The fourth character is the ASCII EOT character (decimal 4).

Example 2: To turn off all ports and the user defined character is ASCII STX (decimal 2).

Send to Master Port: ESC STX STX EOT

(27 2 2 4 decimal)

It is recommended that the user-defined character be a non- printable character. The turn off command will then consist of four characters that will not show up on the current port device.

If you were writing a program in GWBASIC to select port E of the 232D4SS8 (address zero) you would form a string like this:

SW0E$ = CHR$(27) + CHR$(2) + "0" + "E"

You could then send SW0E$ to select port E. Similar strings could be used for turning on the other ports. To turn off the ports the string might look like this:

TOFF$ = CHR$(27) + CHR$(2) + CHR$(2) + CHR$(4)

NOTE: There is no delay through the Smart Switch and the data is not buffered.

The user-defined character comes programmed as the ASCII STX character (decimal 2). You can change this to any 8-bit character you wish by reprogramming DIP switch 2 (SW2). SW2 is located on the printed circuit board inside the 232D4SS8. Refer to Figure 2. SW2 is an eight-position switch with each position equal to a certain weight. Refer to Table 4. It is recommended that a non- printable character be defined.

Documentation Number 232D4SS84502 Manual

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