INT 2Fh... (47)          Multiplex Interrupt                         Overview

Defines a general interface between two processes. Applications using
this interrupt must define specific functions and parameters.
Functions currently defined by DOS include the resident portions of

On entry:      AH         Multiplex number
AL         Function to be performed by multiplex handler

Returns:       AX         Error code


A multiplex handlers is referenced by its "multiplex number," in the
AH register. The choice of multiplex number is arbitrary; you may
assign any number to your routine between 80h and FFh; 0 through 7Fh
are reserved for use by DOS.

The function to be performed by the multiplex handler is specified in
AL. Other registers may hold other parameters, as needed (see the
separate descriptions of the multiplex handlers implemented by DOS).

All multiplex handlers must define a call for AL = 0 (Get Installed
State). AL values of F8h to FFh are reserved by DOS.

Multiplex Handlers Implemented or Reserved by DOS

AH       1h      Resident part of PRINT
2h      Resident part of ASSIGN
10h      Resident part of SHARE
B7h      Resident part of APPEND

All other values from AH = 0 to AH = 7Fh are reserved by DOS.

Interrupt 2Fh is available in DOS versions 3.1 and later.

INT 2Fh... (47) Multiplex Interrupt Overview