OBiTALK Community

General Support => New to Using the OBi / VoIP => Topic started by: trumee on April 16, 2017, 09:28:09 AM

Title: Cat-iq cordless phone for Obihai 202
Post by: trumee on April 16, 2017, 09:28:09 AM
Hello,

I am looking to buy a cordless phone which can make use of the G.722 codec in Obihai. My limited search have revealed phones based on DECT 6.0 only which most likely use G.726 (narrow band codec).

Any recommendations?

Thanks
Title: Re: Cat-iq cordless phone for Obihai 202
Post by: drgeoff on April 16, 2017, 10:57:22 AM
The mandatory codec is G.726 running at 32 kbit/s.

Bear in mind that unless the end to-end-path is using a high quality codec you will get little if any benefit from having it in use in only a part of the path.  The world's traditional telco networks are still almost exclusively G.711 - 8 kbit/s sampling and 8 bit PCM with non-linear quantisation.  And if the distant end is a cellular phone the codecs they use usually give even lower voice quality.

Some telcos have offered HD voice  For example BT in the UK had its 'Broadband Talk' VoIP service which could provide 'HD' capability with its custom DECT phones parented on its early Residential Gateways (BTHomeHubs 1, 1.5 and 2) when communicating with a compatible other end. It didn't make much headway in the market place.  In fact the VoIP and DECT capabilities were not present in any of its later HomeHubs (3, 4, 5 and 6).
Title: Re: Cat-iq cordless phone for Obihai 202
Post by: SteveInWA on April 16, 2017, 03:27:48 PM
Quote from: trumee on April 16, 2017, 09:28:09 AM
Hello,

I am looking to buy a cordless phone which can make use of the G.722 codec in Obihai. My limited search have revealed phones based on DECT 6.0 only which most likely use G.726 (narrow band codec).

Any recommendations?

Thanks

OBi ATAs (20x, 30x) don't support G.722, so there is little advantage to using a wideband-compatible telephone plugged into an OBi ATA.  OBi ATAs support:

G.711 A-Law (64 kbps)
G.711 µ-Law (64 kbps)
G.726 (32 kbps)
G.729a (8 kbps)
iLBC (13.3, 15.2 kbps)

OBi IP phones do include wideband audio CODECs, and they have audio components capable of "HD Voice" or wideband audio.

G.722
G.711 A-Law (64 kbps)
G.711 µ-Law (64 kbps)
G.726 (40, 32, 24, 16 kbps)
G.729a (8 kbps)
iLBC (13.3, 15.2 kbps)
OPUS

And, as drgeoff points out, wideband audio is only useful if the entire call path supports it.