PRT is a predfined device identifier used to reference the printer. However, unlike CRT and KBD which have permanent ISCs assigned to them, PRT's default value of 10 can be assigned a different ISC with the CONFIGURE PRT statement.
CONFIGURE PRT TO 26
PRINTER IS PRT
This way, a printer can be handled just like any other device. The most common device selectors for printers are: 10 (Windows), 9 (serial port), 26 (parallel port), and 701 (GPIB @ primary address 1). These values are default values and may be different on your system if you specified different values when you loaded the device drivers.
SUB Print4(A$) ! subprogram to support 4 printers at once
OUTPUT 9;A$ ! first the serial printer
PRINTER IS PRT ! second the Windows default printer
PRINT A$
PRINTER IS CRT ! back to the CRT
OUTPUT 26;A$ ! next the parallel printer
OUTPUT 701;A$ ! last the IEEE-488 printer
SUBEND
This example uses four "printers" simultaneously. The CRT, plus one printer on the serial port, one on the parallel port, and one on the IEEE-488 bus. The Print4 Sub is used to send output to all four.
