Quote from: Taoman on May 07, 2018, 12:55:23 PM
Is it my imagination or has call quality improved when using SIP with Google Voice?
It is not your imagination. There are fewer hops back and forth between the legacy PSTN and the pure VoIP networks.
Also note: if both ends of the call are pure VoIP, not going through the PSTN, and both endpoints support it, then the calls will be in wideband audio (Opus CODEC), with superb call quality. OBiTALK IP phones support Opus; OBiTALK ATAs do not, as of this posting date.
Examples, assuming both endpoints have OBiTALK IP phones:
You both have Google Voice numbers. The call will be in HD.
You both have Callcentric accounts, and you call using their 1777xxxxxxx on-network numbers. The call will be in HD.
You and your called party both have SIP ITSPs that support Opus, and they have some sort of peering relationship. The call will be in HD.
The long-term, blue sky scenario: a mobile carrier peers with Google Voice, and there is some way to transcode or otherwise magically support the different CODECs used by the mobile carriers, then the call will be in HD. One hurdle at this time, is that fixed VoIP devices typically support Opus, whereas the mobile carriers are using G.722.2 AMR-WB CODEC.