How to Configure Telekom CompanyFlex Sip Trunk in P series PBX

1. SIP Trunk Settings

    1) Basic

  • Transport should choose "TCP"
  • Username is the "Registration Number"
  • Authentication name is the "Registration number +"
  • Outbound-Proxy: is the "primary outbound proxy" which provide by Telekom


    2) Inbound caller ID reformatting


    3) Sip Headers

  • Get Caller ID: FROM
  • GET DID from: P-Called Party ID



2. SIP Settings

    1) General

  • TCP protocol is required
  • SIP endpoint registration timers should be more frequency


     2) Session Timers

  • Session Timer choose No



P.S: If there is an issue when using CompanyFlex sip trunk on P series PBX just feel free to submit a ticket from our support portal





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  • 0


    It works only on a ISP connection directly from Deutsche Telekom. Calls and registration dont work good from other ISP to Deutsche Telekom.

  • 0

    If port 5060 doesn't work, please try to use port 0. 

  • 0

    If it still has the sip trunk registration issue. Please check the exact DNS address offered by Telekom and configure it in PBX’s network settings page. Or any other DNS address would no work. Most of the unable to call in/out issue is caused by invalid DNS configured.
    If the sip provider's DNS doesn't work, please try to use the below DNS to see if it can solve the issue. 


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