ASTERISK CODECS
| Codec | Data bitrate (kbps) | Licence required? |
| G.711 | 64 kbps | No |
| G.726 | 16, 24, or 32 kbps | No |
| G.723.1 | 5.3 or 6.3 kbps | Yes (no for passthrough) |
| G.729A | 8 kbps | Yes (no for passthrough) |
| GSM | 13 kbps | No |
| iLBC | 13.3 kbps (30-ms frames) or 15.2 kbps (20-ms frames) |
No |
| Speex | Variable (between 2.15 and 22.4 kbps) |
No |
