Although this chapter has so far dealt exclusively with CS voice testing, the TEMS Investigation ACU R2 configuration can in fact be used to test the audio quality of any voice service, including OTT services with proprietary protocols such as Skype, Facebook Messenger, Google Talk, and WhatsApp.

This is done by placing a call over the desired service between two connected devices and using the Voice Quality activity as normal in order to obtain AQM data. The fine points of the procedure are covered below.