Int 14 Fn 05  - Connection Manager - Close Communication                   [N]

   AH = 05h
   DX = FFFFh
   AL = connection ID

Return: AH = return code
       00h successful
       01h no such connection
       02h invalid connection ID
       AL = correct connection ID
Desc:  terminate existing connection to allow another one to be established

Note:  if DX is 0-3 on entry, Connection Manager emulates the standard BIOS
     function, but redirects the port over the network; if DX is any other
     value, the call is chained

See Also: AH=04h/DX=FFFFh,AH=0Dh/DX=FFFFh