INT 17H 00H: Print One Character
Expects: AH 00H
AL byte to print. See ASCII and ASCII Control Codes.
DX port number (0=LPT1, 1=LPT2, 2=LPT3)
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Returns: AH Bits set as in PrinterStatusRec (bit 0 set on time-out
error)
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Info: Sends the byte in AL to the specified printer port.
Always check the return code in AH to see if the character made
it to the printer.
Notes: ■ Use INT 11H to see how many printer ports are installed.
■ Please stop writing those applications that write ONLY to LPT1.
That is unutterably frustrating for users.
■ You can write to the PRN device just by using DOS fn 40H with
BX=0004H. You may want to use fn 3eH now and then to flush the
data to the printer.
See Also: INT 17H (BIOS printer support)
ROM-BIOS Functions
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