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    Mobile-X Change Extension-to-Extension Caller ID

    The VoIP Help Page Team·2 min read·Last updated: March 14, 2026

    **Scope**

    This article will go over changing the caller ID for extension-to-extension Mobile-X calls.

    Requirements

    Since calls using Mobile-X technically have to be routed over mobile or PSTN networks, extension numbers cannot be used for caller ID for extension-to-extension calls with . As an alternative, we provide a few different alternatives:

    • Number Transform (extension suffixed at the end of a default DID): +1 (555) 555-<extension> (ie +1 (555) 555-1234) (Default)
    • A Main Number for all extensions
    • An Assigned Number for a Range of extensions
    • A specific Source Extension DID

    Configure a Number Transform

    1. 1

      In the Mobile-X Control Panel, navigate to Groups > the name of the group you'd like to edit > Numbers > Edit Transform Settings

    2. 2

      Switch Default Transform to On and set the Extension Length to the length of the extensions on the PBX domain (usually 3 or 4 digits)

    3. 3

      Select Save

    4. 4

      In the Mobile-X Control Panel, navigate to Groups > the name of the group you'd like to edit > Numbers > Number Transforms

    5. 5

      Switch Force a Main Number as the Calling Line ID for all Extensions to On

    6. 6

      Select Save

    7. 7

      Select Add Range

    8. 8

      Enter the following information into the modal that pops up:

      1. 1
        Name: Range Name
      2. 2
        Range Start: The first extension in the range (ie '1000')
      3. 3
        Range End: The last extension in the range (ie '1099')
      4. 4
        Assigned PBX: UCAASNetwork
      5. 5
        Main Number: The number you want to show for extension-to-extension calls from this range
    9. 9

      Select Save

    10. 10

      In the Mobile-X Control Panel, navigate to Groups > the name of the group you'd like to edit > Numbers > Number Transforms

    11. 11

      Select Add Transform

    12. 12

      Enter the following information into the modal that pops up:

      1. 1
        Source Number: The extension you'd like to set the caller ID for
      2. 2
        Mapped E.164: The caller ID shown on the Mobile-X device
    13. 13

      Select Save

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