Commodore Plus 4 - Page 385

The Printer 373
where filenumber is the logical file number to which output should be directed.
Once this command is executed, all output that would normally go to the screen
goes to the named file instead. So, to list a program, type
0PEN4,4:CMD4:LIST
PRINT#4:CL0SE4
The PRINT#4 is needed to restore the default output device to the screen and to
tell the printer to stop listening on the serial bus.
When output to the printer is finished, the file should always be closed using
CLOSE filenumber
where filenumber is the logical file number used for the printer. To ensure that the
printer's internal buffer has been emptied, and a stop listening command sent, the
last data byte sent to the printer should be a carriage return. Usually, in a
program, this happens to be the case. When it is not, the CLOSE command
should be preceded by
PRINT*filenumber
The second method of directing data to the printer is with the PRINT#
command. Every character sent to the printer is interpreted as a command or
data. Generally, CHR$ codes of 32 through 127, and 160 through 255 are
printable characters whereas other values may be control characters. The inter
pretation of CHR$ codes depends on the particular printer; check your manual.
For the MPS-801, the following control codes are available:
8 = enter dot mode
10 = linefeed (and carriage return)
13 = carriage return (and linefeed)
14 = enter double width character mode
15 = enter standard width character mode
16 = set the print head position
17 = switch to upper/ lower case
18 = turn on reverse field
26 = repeat dot pattern
27 = specify dot address for print head