Advanced configuration
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Advanced configuration

After you have configured the basic settings, there are a number of advanced settings you can change. These are visible when you tap on the profile account and can be configured differently per account.

Audio Options

The following audio options are available in the Audio Settings section.

  • Echo cancellation – If set, enables echo cancellation during calls
  • Silence detection – If set, enables silence detection during calls
  • Play Buffer – Higher values improve quality but increase latency
  • Record Buffer – Higher values improve quality but increase latency
  • Mic Gain – Amplifies the microphone input

Audio Codecs

In the Audio Settings section, you can configure the preferred codec to be used.

3CXPhone supports 4 codecs. These are GSM, G.711 (uLaw), G.711 (aLaw), and Speex. Whilst G.711 gives you the highest quality, it also consumes the most bandwidth. Therefore you may configure your codec priority such that GSM will be used first if available. To change codec priority simply move the preferred codecs upwards.
You also have the option to disable the audio codecs you do not intend to use by disabling the checkbox. In this example we can see that GSM was placed first, followed by PCMU, PCMA and the Speex codec has been disabled.


In the “Other Settings” section we have advanced options which allow you to configure advanced SiP and networking options.

  • Local SiP Port – Configure the Local SiP port that the phone will use LOCALLY on the Android Device (Source SiP Port)
  • Registration Timeout – Timeout in seconds that the REGISTER will expire. After this timeout a new REGISTER request will be sent
  • Keep-Alive Interval – Interval that Keep-Alives will be sent. These are packets to keep the connection alive
  • DTMF Method – The type of DTMF that will be used when a digit input is pressed – Available options are In-Band, RFC-2833, Sip-Info. The most widely used is RFC-2833 and this is set as the default option.
  • TCP transport – If this option is enabled, the 3CX Phone for Android will send SiP over TCP
  • NAT Helper – A module to help with NAT traversal which helps determine public ip address in symmetric NAT conditions
  • Enable ICE – Enables Interactive Connectivity Establishment which uses STUN and it’s extension TURN


The following settings refer to the level of integration with your phone

  • International Code (+) – Configure how the + should be converted example 00 or 01
  • Phonebook prefix– Add a prefix that will be prepended to all calls you dial from the phonebook
  • Lock Wi-Fi – This option will receive calls in the background, even when the screen of your phone is off. However, this requires a continuous connection to WIFI and thus reduces battery-life
  • Enable 3G – If this option is enabled, 3G will be used to setup VoIP Calls when 3G is available. It is possible to switch this off in case your provider has problems with or blocks VoIP calls over 3G
  • Redirect normal calls – If set, then any calls that you make on the normal dial pad will be re-routed via VoIP if a connection is available
  • Log call records – If set, all calls made with 3CXPhone will be included in the standard phone call history

  • Record calls – If set, calls made with 3CXPhone will be recorded to file in mp3 format
  • Full Screen – 3CX Phone in full screen. This requires restart. If this is enabled, then the notification bar at the top will be hidden. It is recommended to disable this so you can see the WiFi Signal, notifications etc.
  • Proximity Sensor – Used to block input to the screen during a connected active call. During a conversation it may occur that your cheek touches the Android phone display screen. In this case DTMF digits can be sent or the call may be accidentally disconnected. To prefent this enable this option and 3CX Phone will block input to the screen