VoIP

Last Updated : Aug 30, 2026 |
Navigation: System SettingsSystemVoIPVoIP
Prolog information
Metadata
Keywords:
This tab is used to set the codecs available for use with all IP lines and extensions and the default order of codec preference.
  • Avaya H.323 telephones do not support G.723 and ignore it if selected.
  • For IP Office systems with H.323 lines and extensions, one of the G.711 codecs must be selected.
  • G.723 and G.729b are not supported by Linux-based IP Office systems.
  • The number of channels provided by an IP500 VCM 32 or IP500 VCM 64 card, up to a maximum of 32 or 64 respectively, depends on the actual codecs being used. This also applies to IP500 VCM 32 V2 and IP500 VCM 64 V2 cards. The following table assumes that all calls using the VCM use the same codec.
    Codec
    IP500 VCM 32 IP500 VCM 32 V2
    IP500 VCM 64 IP500 VCM 64 V2
    G.711
    32
    64
    G.729a
    30
    60
    G.723
    22
    44
    G.722
    30
    60
Paging from an IP device uses the preferred codec of that device. It is the system administrator's responsibility to ensure all the target phones in the paging group support that codec.
These settings must be edited offline. To enter offline editing, select Menu Bar Current User IconOffline Mode.
Field
Description
Ignore DTMF Mismatch for Phones
Default = Enabled.
When enabled, the following settings are visible and configurable:
  • Call ManagementExtensionsEdit ExtensionH323 VoIPRequires DTMF
  • Call ManagementExtensionsEdit ExtensionSIP VoIPRequires DTMF
When enabled, during media checks, the system ignores DTMF checks if the call is between two VoIP phones and the extension setting Requires DTMF is set to Off. The two phones can be located on different systems in a Server Edition or SCN deployment.
Allow Direct Media Within NAT Location
Default = Off.
When enabled, the system allows direct media between devices that reside behind the same NAT. Devices are behind the same NAT if their public IP addresses are the same.
  • Direct media may still not be possible if other settings, such as codecs, NAT settings, or security settings do not match.
The default behavior is to allow direct media between all types of devices (H323 and SIP remote workers and IP Office Lines behind a NAT). In the case of routers that have H323 or SIP ALG, it can be desirable to allow direct media only between certain categories of devices. This can be configured by adding the NoUser Source Number MEDIA_NAT_DM_INTERNAL. For information, see Call ManagementUsersAdd/Edit UsersSource Numbers.
Disable Direct Media For Simultaneous Clients
Default = Disabled
If enabled, the Allow Direct Media Within NAT Location settings for virtual extension records is disabled.
RFC2833 Default Payload
Default = 101. Range = 96 - 127.
This field specifies the default value for RFC2833 dynamic payload negotiation. Service providers that do not support dynamic payload negotiation may require a fixed value.
OPUS Default Payload
Default = 116.
This field specifies the default value and the range to be used for Opus codec.
This field is only used for Linux-based systems.
Note:
This field is not avialable on IP500v2, but the Unknown Codec passthrough and the OPUS settings are available to set individually.
Available Codecs
This list shows the codecs supported by the system and those selected as usable. Those codecs selected in this list are then available for use in other codec lists shown in the configuration settings. For example, the adjacent Default Selection list and the individual custom selection list on IP lines and extensions.
Other:
Removing a codec from this list automatically removes it from the codec lists of any individual lines and extensions that are using it.
The supported codecs (in default preference order) are: Opus, G.711 A-Law, G.711 U-Law, G.722, G.729, and G.723.1. The default order for G.711 codecs varies to match the default companding settings of the system. G.723.1 and G.729b are not supported on Linux- based systems.
Default Codec Selection
By default, all IP (H.323 and SIP) lines and extensions added to the system have their Codec Selection setting set to System Default. That setting matches the codec selections made in this list. The buttons between the two lists can be used to move codecs between the Unused and the Selected parts of the list and to change the order of the codecs in the selected codecs list.
Related links
VoIP