help with grandstream 4004 on 3cx

Discussion in '3CX Phone System - General' started by slippers, May 3, 2011.

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  1. slippers

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    hi
    just setup a grandstream 4004 in order to fax out via 3cx / SIP
    using the little handset on the fax I can dial an internal extension and all works fine
    however when we dial an external number, the other party phone rings and they hear me but we cant hear them.

    extension assigned to grandstream is registered in 3cx

    reset grandstream to factory and rebuilt and still get same results
    any ideas ? :)
     
  2. leejor

    leejor Well-Known Member

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    Is this the first (and only) extension you have set up? Do others work?

    What does the 3Cx server log show during a call attempt?

    No RTP packets received?

    If so, then run the firewall checker, and be sure that all of the required ports are forwarded in your router.
     
  3. paul1

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    If the 4004 is registered to a fax extension then I think you are having issues with the codec being forced to t.38 (because it is defined as a fax extension.) If you register it to a regular extension it should work for voice. Have you tried to receive a fax on it?
     
  4. GSsupport

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    Hi slippers,

    According to your description, the issue is only for incoming RTP for external calls, this means that your router is blocking incoming RTP stream from external
    I suggest you to check if the needed ports for incoming RTP stream are open on your router.

    B. regards,
    GSsupport
     
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