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Communication 7156 Owner’s Guide

October 199562

Using DOS to Send Commands

One way of getting commands to the printer is to send them directly from DOS.

For example, the command

COPY CON: COM1:

sets the computer up such that the Hex code corresponding to any key that was

pressed would be sent to the RS-232C communication port COM1 when the

COPY mode is exited. If the printer is connected to COM1, then the data will go

to the printer.

Exit the COPY mode by typing

CTRL Z

and then pressing the ENTER key. Once the computer knows to direct data from

any print command to the proper port, commands can be sent from any software

program.

Using BASIC to Send Commands

In BASIC, printer commands are sent as a string of characters preceded by the

LPRINT command. For example,

LPRINT CHR$(&H0A)

sends the hexadecimal number 0A to the printer, which causes the printer to

print the contents of its print buffer. Previously sent commands tell the printer

exactly how this data should appear on the paper. For example,

LPRINT CHR$(&H12); "ABC"; CHR$(&H0A)

sends the Hex numbers 12 41 42 43 0A to the printer. This causes the printer to

set itself to double wide mode (12), load the print buffer with “ABC” (41 42 43),

and finally, print (0A). Again, the communication link that the BASIC program

outputs to must be matched to that of the printer.

RS-232C Interface

The RS-232C interface uses either XON/XOFF or DTR/DSR protocol. For

XON/XOFF, a particular character is sent back and forth between the host and

the printer to regulate the communication. For DTR/DSR, changes in the

DTR/DSR signal coordinate the information flow.

The RS-232C version of the 7156 offers the standard options which are selected

with the DIP switches. See “Switch Settings” later in this chapter.

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Axiohm 7156 Especificaciones Pagina 70