[MSDN Library June 1998] Tone Monitoring (58.6993970714901%)
MSDN Library Visual Studio 6.0 > Platform SDK > Networking and Distributed Services > Telephony Application Programming Interface (TAPI) > TSPI Version 2.1 > Overviews > Line Devices > Supplementary Line Services > Monitoring
[MSDN Library June 1998] Tone Monitoring (49.6193244739756%)
MSDN Library Visual Studio 6.0 > Platform SDK > Networking and Distributed Services > Telephony Application Programming Interface (TAPI) > TAPI Version 2.1 > Overviews > Supplementary Line Functions > Call Monitoring