Commodore MPS-801 User Manual page 24

physical device. The
logical file number
(lfn) may be any number from I
to 255. It doesn't matter which number you choose, as long as you keep
the same number throughout your set of commands.
The
device number
(dn) refers to the device to which you send the file.
The first device number is also known as the primary address. If you are
using a MPS-SOI printer, the dn (device number) is usually 4. Check the
test switch on your printer to see what dn to choose.
The secondary address (sa) is an optional and unique printer concept.
Secondary addresses on this printer provides
the
following printer options.
Sa= 0: Print data exactly as received
Sa=
6:
Setting spacing between lines
Sa= 7: Select business mode
Sa= S: Select graphic mode
Sa=10: Reset the printer
The SYNTAX for the OPEN Command is:
OPEN Ifn, dn
OPEN 99,4
OPEN
2,4
The CMU Command
or
or
or
OPEN lfn, dn, sa
OPEN 1,4,0
OPEN
26,4,7
The CMD command transfers control from the computer to the printer.
The lfn (logical file number) must be the same as the one you chose for
the OPEN command. If you are using more than I OPEN command, each
CMD command must have the same number as the corresponding OPEN
command. Unlike a PRINT# command (which is discussed next), the line
to the receiving device (in this case your printer) is left open. The device
given the CMO command is said to be "listening." That means that once
you give the CMD command, your printer will print READY and it will
then be open and waiting for further instructions. At this point, any
PRINT or LIST command will go directly to the printer as output.
The SYNTAX for the CMD Command is:
18.
CMO lfn
CM099
CM02
(notice that the CMD logical file numbers correspond to the
OPEN Ifn's)