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 #0230)
   AL = modem status (see #0231)
   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 serial line status:
Bit(s) Description (Table 0230)
 7 timeout
 6 transmit shift register empty
 5 transmit holding register empty
 4 break detected
 3 framing error
 2 parity error
 1 overrun error
 0 receive data ready

Note:  for COMM-DRV, if bit 7 is set, an error occurred, and may be retrieved
     through a separate call (see AX=8000h"COMM-DRV")

Bitfields for modem status:
Bit(s) Description (Table 0231)
 7 carrier detect
 6 ring indicator
 5 data set ready
 4 clear to send
 3 delta carrier detect
 2 trailing edge of ring indicator
 1 delta data set ready
 0 delta clear to send