INT 14 - ARTICOM - SET INTERNAL SEND/RECEIVE VECTOR
        AX = 8025h
        DS:DX -> address of trap function (see below) to call on read/write
Note:   setting the vector to a user function allows the redirector's activity
          to be monitored.
SeeAlso: AX=8000h,AX=8035h,INT 21/AH=25h

Trap function called with:
        AH = operation
            80h reading character
            81h writing character
        AL = character
        Return: AX must be preserved
                far JUMP to old trap function (see AX=8035h)

.