atcomsystems.ca/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones Voice Coding Option

I have been trying to learn something about VOIP. My question is what voice coding options you are using. I see that some of the VOIP sets will work with G.711, ADPCM, and G.729. Just a question about the real world of VIP.

G7.11 = no compression. G7.29 = compression.

Both G.711 and G.729 are CODECS that are a VoIP standard through which voice information can be encoded into data or decoded back to voice information. Both a Coder and Decoder are necessary on both sides of the telephone call since telephone calls occur simultaneously in both directions. Bandwith is extremely important in maintaining a clear voice path from one point to the next, therefore it is important that all types have the capabilites to :

1. Provide low bandwith (the ability to compress voice data.)
2. Providee high quality for voice calls.
3. Battle against low latency.
4. Reconstruct lost packets.

CODEC G.729 is most favored because it saves available bandwith utilizing high compression/low bandwith and is comparable to cellular phone quality. While CODEC G.711 is not feasible on most networks since it offers low compression/high bandwith and is considered "toll quality" for voice.

There a a multitude of CODEC's out there, but I'm only familiar with G.711, G.726 and G.729. Maybe someone else has knowledge of ADPCM and the benefits of that CODEC. ADPCM isn't even listed in my VoIP reference material.

G.726 is ADPCM

https://business.cisco.com/glossary...ic_view=true&kbns=2&DefMode=.htm

See there RT you taught me something. I've never seen the two referenced before.

I may not know VOIP but I do know Voice coding. SWBT had a Subscriber Loop Carrier (SLC40) deployed that used ADPCM (G.726). The SLC40 had 40 channels working on a T1 Line. They were replaced because FAX machines and data modems would not work on them.