Junction Networks OnSIP Also Supports HD Voice

OK, so this isn’t exactly news. I’ve been using OnSIP with Polycom IP650 & 550 and a few months already. I hadn’t expected them to support wideband at all but was pleasantly surprised to find that their new conference bridge handles it just fine.

Further, if you’re using suitably capable Polycom or snom phones then calls placed through OnSIP will negotiate to G.722 and voila, much clearer calling. They had a blog post about it a short while ago.

Of course, this potential only applies to calls between extensions on the service and calls to/from SIP URIs wherever they originate. Calls that hit the PSTN are negotiated down to G.711 as per usual. Even so you get above average call quality since the HD capable phones are just simply better, both acoustically and electrically.

I’ve also used the Eyebeam soft phone with OnSIP to good effect. As noted earlier Eyebeam and the Polycoms don’t play well together using G.722. Calls between these two end-points have problems because of an oddity in RFC3551 that specifies G.722. The RFC stipulates:

Even though the actual sampling rate for G.722 audio is 16,000 Hz, the RTP clock rate for the G722 payload format is 8,000 Hz because that value was erroneously assigned in RFC 1890 and must remain unchanged for backward compatibility. The octet rate or sample-pair rate is 8,000 Hz.

The end result is that the Polycom phone simply does not play the audio stream presented by the Eyebeam client. I’ve posed a question about this to a contact at Polycom and hope for an explanation of their position.

However, it seems that conference bridges overcome this problem. Both the OnSIP and ZipDX conferences support wideband conferences, and they sound great! Truly, conferencing is one area where wideband presents a tremendous advantage over traditional telephony.  The improved intelligibility is more than just impressive, it’s genuinely usefull.