SecureLogix product can monitor and control traditional POTS voice and also VoIP (SIP and H.323v2) The ETM 1090 system can capture digital recordings of any call and record up to eight simultaneous calls off one voice span. This is clearly a wiretap if there ever was one. I recommend using such a system to implement voice policies, and tread very carefully when considering call monitoring. ETM gives no indication to call participants that they are being recorded; check with your legal department before implementing any recording scheme.”]
Source: https://taosecurity.blogspot.com/2005/03/securelogix-enterprise-telephony.html