The VoIP enabled Nokia S60 devices support the following codecs with the SIP VoIP calls:
- AMR NB (AMR NB—adaptive multi-rate narrow band is the mandatory speech codec for third generation (3G) networks that provides mobile telephony applications with compression of toll-quality speech)
- PCMU (G.711 μ-law, a standard used in circuit-switched telephone networks mainly in USA and Japan)
- PCMA (G.711 A-law, a standard used in circuit-switched telephone networks mainly in Europe and other countries outside USA and Japan)
- iLBC (iLBC—Internet low bit rate codec, suitable for robust voice communication over IP)
- G.729 (used for coding speech signals at 8 kbps)
- Comfort Noise (not a separate codec, but handled as such, can be used together with iLBC, PCMU and PCMA codecs)
The codec order is fixed and can be changed only with special tool programs (e.g. with SIP VoIP Settings application found at Nokia Developer site, Nokia Configuration Tool or with OMA DM based Device Management products).
The selected codec depends on the codecs supported by the peer side, the first matching codec will be used when establishing the VoIP call with the peer.