Int 14H [PS/2] Function 04H Extended initialize communications port

Initializes a serial communications port to a desired baud rate, parity, word length, and number of stop bits. Provides a superset of Int 14H Function 00H capabilities for PS/2 machines.

Call with:

AH = 04H

AL = break flag

00H no break

01H break

BH = parity

00H none

01H odd

02H even

03H stick parity odd

04H stick parity even

BL = stop bits

00H 1 stop bit

01H 2 stop bits if word length = 6—8 bits

01H 1.5 stop bits if word length = 5 bits

CH = word length

00H 5 bits

01H 6 bits

02H 7 bits

03H 8 bits

CL = baud rate

00H 110 baud

01H 150 baud

02H 300 baud

03H 600 baud

04H 1200 baud

05H 2400 baud

06H 4800 baud

07H 9600 baud

08H 19,200 baud

DX = communications port number (0 = COM1, 1 = COM2, etc.)

Returns:

AH = port status (see Int 14H Function 00H)

AL = modem status (see Int 14H Function 00H)