Codecs on SIP phones

Yealink T31P 

 Grandstream GRP-2602P 

 Cisco SPA-303 

 Linphone 

 

 

 Versions 

 FW  124.86.0.40 HW  123.1.1.0.2.0.0 

 

 

 Boot  1.0.1.32 Core  1.0.5.17 Prog  1.0.5.5 Locale  1.0.5.40 Res  1.0.5.1 

 

 

 

 Software Versions: 

     7.4.9c, 7.5.2 

 Hardware Version: 

     1.0.1 

 

 

 Android 9+: 

     v6.2.3 (7 Jul 2026) 

 

 

 

 in order of priority 

 

 Opus 

 G722 

 PCMA 

 PCMU 

   

 legacy: 

   

 G729AB 

 G729 

   

 G726/40 kbps 

 G726/32 kbps 

 G726/24 kbps 

 G726/16 kbps 

   

 iLBC/15.2 kbps 

 iLBC/13.3 kbps 

   

 G723.1/63 kbps 

 G723.1/53 kbps 

   

   

 

 

 Opus 

 G722 

 PCMA 

 PCMU 

   

 legacy: 

   

 G.729A/B 

   

   

 G.726-40 kbps 

 G.726-32 kbps 

 G.726-24 kbps 

 G.726-16 kbps 

   

 iLBC 

   

   

 G.723.1 kbps 

 

 

 not supported: Opus 

 1) G722 

 G711u 

 G711a 

   

 legacy: 

   

 2) G729a 

   

   

 3) G726-40 

 G726-32 

 G726-24 

 G726-16 

 

 not supported: iLBC 

   

   

 not supported: G.723 

   

   

 

 

 

 Opus/48 kHz 

 G722/8 kHz 

 PCMU/8 kHz 

 PCMA/8 kHz 

   

 legacy: 

   

 G729/8 kHz 

   

 

 not supported: G.726 

   

   

   

   

 iLBC/8 kHz 

   

   

 not supported: G.723 

   

 other codecs enabled: 

 L16/44.1 kHz 

 speex/32kHz 

 speex/16 kHz 

 iSAC/16 kHz 

 BV16/8 kHz 

 GSM/8 kHz 

   

 (priority order can not be defined in the admin UI) 

 

 

 

 Config variables 

 

 

 

 Use Pref Codec Only: no 

 G729a Enable: yes 

 G722 Enable: yes 

 G726-16 Enable: no 

 G726-24 Enable: no 

 G726-32 Enable: no 

 G726-40 Enable: yes 

 Release Unused Codec: no 

 Use Remote Pref Codec: yes 

 Codec Negotiation: list all