Int 2F Fn 5600  - Interlnk - Installation Check                            [R]

   AX = 5600h
   DX = magic value FFFFh
   BL = instance number (00h = any, 01h = first loaded, etc.)

Return: AL = FFh if installed
       BL = instance number
       CX = version number (CL = major, CH = minor)
       DX = resident CS of driver, DX:0000h -> header (see #2531)

See Also: AX=5601h,AX=5602h,INT 60/AX=0000h

Format of Interlnk device driver header:
Offset Size    Description (Table 2531)
 00h   DWORD   pointer to next driver, offset=FFFFh if last driver
 04h   WORD    device attributes (see #1333,#1334)
 06h   WORD    device strategy entry point
 08h   WORD    device interrupt entry point
 0Ah  8 BYTEs  character device name "NUL2    "
 12h 165 BYTEs ???
 B7h 67 BYTEs  fully qualified Interlnk filename
 FAh  6 BYTEs  ???
100h   DWORD   pointer back to Interlnk filename at offset B7h
104h  8 BYTEs  ???
10Ch   BYTE    total number of redirected drives
10Dh   BYTE    first local drive number (0=A:)
10Eh   BYTE    printer redirection (0=no, 1=yes)
10Fh   BYTE    ???
110h  3    BYTEs   LPT1...3 status (0FFh=invalid)
113h 26 BYTEs  remote drive number (0=A:, 0FEh=unused) (refer to note below)
12Dh 26 BYTEs  always 0FEh ???
147h 26 BYTEs  always 0FFh ???

Note:  to obtain the remote drive number, subtract the value at offset 10Ch
     from the local drive number before indexing into the table at 113h
     (example: if local drives F, G, H are remote drives C, F, E then
     the first three bytes at offset 113h are 02h, 05h, 04h)
   for each instance of Interlnk, an extra device driver is loaded, but
     all have the same device name NUL2

See Also: #1332 at INT 21/AH=52h