SIP Phone Context Parameter


The "Phone-Context" parameter is defined in RFC 3966 and is part of the URI scheme "tel". Feature 1584 adds to the IMG support for the "Phone Context" parameter on the outgoing To/From headers in the SIP INVITE message. The "Phone Context" feature is configured in the SIP SGP Profile and is disabled by default. See below



3966 - The tel URI for Telephone Numbers



Call Trace Example:

Click HERE for Call Trace of a SIP to SIP call.



Call Flow Diagram:

Below is Call Flow Diagram for the Call Trace above showing the Phone Context Value.






The 'Phone Context' parameter is configured through the SIP SGP Profile. Below are steps to configure the IMG to output the Phone Context parameter in the SIP INVITE message.

  1. Right click on the Dialogic IMG EMS object and select New Profiles. This will create a Profiles object.

  2. Right Click on the Profiles object and select New SIP SGP. This will create a new Gateway Profile object as shown on screen capture below. The Phone context support fields are at bottom of this object pane. In order to be able to edit the SIP SGP Profile, change the ID to something other than ID:0. ID:0 is reserved as a default Gateway profile.


  3. The Phone Context Support feature is disabled by default. To enable select from drop down menu where to include the 'Phone Context' parameter. See screen capture below.


    Include in To: Header - Include the Phone Context Parameter in the To: Header only.
    Include in From Header - Include the Phone Context Parameter in the From: Header only.
    Include in both To: and From: Headers - Include the Phone Context Parameter in both the To: and From: Headers.

  4. Click in the 'Phone Context String' field and enter the Phone Context String. Max number of characters is 64. Below are a few examples:

    Digit String = 1508862
    Domain Name =

  5. Once the Phone context parameters are entered into the Phone Context fields then the SIP SGP Profile will be available in one of the following SIP Panes:

    SIP Signaling Object:

    SIP External Gateway:

Additional Information:


Related Topics:

SIP Profile