Int 5C  - IBM 802.2 Interface (llc)                                        [N]

   ES:BX -> CCB (see below)

Return: none

Format of CCB:
Offset Size    Description
 00h   BYTE    adapter
 01h   BYTE    command code
 02h   BYTE    return code
 03h   BYTE    work
 04h   DWORD   pointer to ???
 08h   DWORD   pointer to completion function???
 0Ch   DWORD   pointer to parameters???