BER testing tool
----------------

* Check all configs (MSC/BSC/BTS) for proper codec support
  - FR enabled
  - EFR enabled
  - AMR 12.2 enabled (and all other modes disabled !)
  - Use `amr-payload octet-aligned` in BSC config

* Check BTS config
  - Disable jitter buffer : `bts N / rtp jitter-buffer 0`

* Check BSC config
  - Disable radio timeout : `network / bts n / radio-link-timeout infinite`

* Start BER testing tool
  - `./rtp_ber 4000`

* On the MSC CLI, start a silent-call, then request GSM to test loop
  - `subscriber imsi <XXX> silent-call start tch/f speech-amr`
  - `subscriber imsi <XXX> ms-test close-loop b`

  Don't forget to terminate the loop and terminate the silent call !

  - `subscriber imsi <XXX> ms-test open-loop`
  - `subscriber imsi <XXX> silent-call stop`