INT 14 - Digiboard DigiCHANNEL PC/X* - READ STRING
AH = 0Fh
CX = number of characters to read
ES:BX -> buffer
DX = port number (00h-03h) (04h-43h for XAPCM232.SYS)
Return: AX = number of characters read
ZF clear if successful
ZF set on error (line status or wrong number of characters)

See also: 140E

140F - Digiboard DigiCHANNEL PC/X* - READ STRING