Int 6B Fn 21  - Npc Ncsi Extended Serial I/o - Query Name Service          [S]

   AH = 21h
   AL = virtual circuit number
   CL = ??? (00h or 01h)
   ES:BX -> buffer for service name structure (see #3403)

Return: CF clear if successful
       ES:BX buffer filled
   CF set on error

Notes: a program should call this function after allocating a virtual circuit
     and check that the general name matches the requested service
   prior to version 3.0, Novell's NASI returned the first available port;
     v3.0+ returns the first port found--check the returned status to
     determine whether the port is available

See Also: AH=14h"NCSI"

Format of NCSI service name structure:
Offset Size    Description (Table 3403)
 00h   WORD    buffer length
 02h  8 BYTEs  service name
 0Ah  8 BYTEs  general name
 12h  8 BYTEs  specific name
 1Ah  4 BYTEs  ???
---Novell NASI v3.0+ ---
 1Eh   BYTE    port number
 1Fh   BYTE    port status
       00h idle (available)
       01h allocated (available)
       02h connected
       03h on hold