Int 2F Fn CB00  - Communicating Applications Specification - Installation  [F]

   AX = CB00h

Return: AL = status
       00h not installed, OK to install
       01h not installed, not OK to install
       FFh installed

Note:  AH = CBh is the default identifier, but may be reconfigured

See Also: AH=2Ah,AX=8000h"FaxBIOS",AX=CB0Eh,AX=CBDCh