MOS Score - G.726 ADPCM & G.729 CS-ACELP - Voice Quality issues?

Hi DSP Related members,

I am researching to find out information on the voice quality of codecs used for VoIP communication using networking routers, switches and access devices.

The main objective is that the MOS (Mean Opinion Score) should be greater than 3.82 on the scale of 1 (poor quality) and 5 (best quality).

Is the Codec G.726 ADPCM (32 Kbps) with a MOS of 3.85 is used in the real-world IP (Internet Protocol) networks, right now?
What are the problems encountered by G.726 ADPCM Codec in the VoIP real world applications? (like compatibility with other devices and equipments; whether fully supported for end -to-end communication between source and destination users; etc)

The other Codecs with more than 3.82 MOS score are:
G.711 PCM; G.729 CS-ACELP (8 bits) and G.723.1 MP-MLQ (6.3 bits), but I would appreciate the DSP Related members providing me information on:
What are the problems and issues encountered in the real-world VoIP applications, if these Codes are used (like compatibility with other devices and equipments; whether fully supported for end -to-end communication between source and destination users; etc)?

Any information is highly appreciated.

Best regards,

Raj Start a New Thread