How to configure a FritzBox for QSC

On August 8, 2017, in FritzBox, QSC, VoIP, by terencejackson

Long overdue I finally decided to upgrade to VoIP phone lines for my company. After some research the decision was to go with QSC. We chose a SIP trunking phone product only, internet is from a different provider.

The setup itself seems to be quite simple. I have a Fritz!Box 7430 which servers as the internet router as well the DECT base. All phones are connected to that Fritz!Box via DECT.

The biggest problem I was facing was, that after setting up the SIP connection on the Fritz!Box, I was “online” but for outgoing calls always my base number was displayed (a 03221 number) and incoming calls were not able to be connected at all.

After multiple calls with the QSC call center I got to the following result

1) In the “from field” the User ID was sent and not the calling phone number

2017-08-04 09:04:01 +0200 : -> INVITE SIP/2.0
Via: SIP/2.0/UDP;branch=z9hG4bK63ocu310781hcbj5m3g1.1
From: <sip:xxxxxxxxxxxxxx@>;tag=SD2v22201-7X3F7007A972XXAA
To: <sip:callingnumber@>
Call-ID: SD2v22201-xx1e50bc307186x53xx1b25723b083be-l65h8l3
Contact: <sip:xxxxxxxxxxxxxx-lr9lt3d1l03e3@;transport=udp>
Max-Forwards: 69
Expires: 120
User-Agent: AVM FRITZ!Box 7430 146.06.83 (Feb 24 2017)
Supported: 100rel,replaces
Allow-Events: telephone-event,refer

2) The Fritz!Box is giving a 404 for incoming calls

2017-08-04 09:06:08 +0200 : ->
SIP/2.0 404 Not Found
Via: SIP/2.0/UDP;branch=z9hG4bK2c6d.034fdecef8a0f4ba56a4161e01abd82a.0
Via: SIP/2.0/UDP;branch=z9hG4bKal81sa7a5n52lsq12n19e0q7r
Call-ID: 981hshr597a7l8h50rn5lnea8nqq5l4n@SoftX3000
To: <sip:+49711xxxxxxxxx@;user=phone>;tag=SDqsjm999-C1822487D7FFC479
From: “+callingumber” <sip:+callingumber@;user=phone>;tag=srlqqhan-CC-32
User-Agent: FRITZ!OS
Content-Length: 0

So far so good. Unfortunatelly the QSC support could not help me out any more than this giving the statement: “That’s your problem. The Fritz!Box is not whitelisted for QSC and that’s why we can and will not support you with this”.

After some researching I finally found out the settings with which I was able to receive incoming calls and show the correct phone number when calling someone.

  1. The phone number for the registration has to be in the format <country code><phone number>
    1. e.g 49711xxxxxxx
  2. The “Rufnummerübermittlung” has to be set to “Rufnummer im Display und Namen”



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