Int 14 Fn 03  - Serial - Get Port Status                                   [S]

   AH = 03h
   AL = 00h (ArtiCom)
   DX = port number (00h-03h) (04h-43h for Digiboard XAPCM232.SYS)

Return: AH = line status (see below)
   AL = modem status (see below)
   AX = 9E00h if disconnected (ArtiCom)

Note:  the 04/08/93 Compaq system ROM uses only the low two bits of DX

See Also: AH=00h,AH=07h"MultiDOS",AX=8000h"ARTICOM",AH=81h"COURIERS",AX=FD02h

Bitfields for line status:
 bit 7 timeout
 bit 6 transmit shift register empty
 bit 5 transmit holding register empty
 bit 4 break detected
 bit 3 framing error
 bit 2 parity error
 bit 1 overrun error
 bit 0 receive data ready

Bitfields for modem status:
 bit 7 carrier detect
 bit 6 ring indicator
 bit 5 data set ready
 bit 4 clear to send
 bit 3 delta carrier detect
 bit 2 trailing edge of ring indicator
 bit 1 delta data set ready
 bit 0 delta clear to send