Int 21H [1.0] Function 05H Printer output

[1] Sends a character to the first list device (PRN or LPT1).

[2.0+] Sends a character to the standard list device. The default device is the printer on the first parallel port (LPT1), unless explicitly redirected by the user with the MODE command.

Call with:

AH = 05H

DL = 8-bit data for output

Returns:

Nothing

Notes:

If the printer is busy, this function waits until the printer is ready to accept the character.

There is no standardized way to poll the status of the printer under MS-DOS.

If a Ctrl-C is detected at the keyboard, an Int 23H is executed.

[2.0+] You can also send strings to the printer by performing a write (Int 21H Function 40H) using the predefined handle for the standard printer device (0004H) or using a handle obtained by opening the logical device PRN or LPT1.

Example:

Output the character "*'' to the list device.

.

.

.

mov ah,5 ; function number

mov dl,'*' ; character to output

int 21h ; transfer to MS-DOS

.

.

.