Int 61 Fn 30  - Atari Portfolio - File Transfer Services                   [b]

   AH = 30h
   AL = function
       00h transmit block
       CX = number of bytes to send
       01h receive block
       CX = buffer size
       02h open ports
       03h close ports
       04h wait 500ms
   DS:DX -> start of data buffer

Return: DL = status
       00h successful
       01h buffer too small
       02h transmission timeout
       03h checksum failure
       04h invalid subfunction
       05h peripheral not installed
   if function 01h:
       CX = number of bytes received

See Also: AH=00h"Portfolio",AH=2Eh"Portfolio"