Cisco 7940/60 Integration with third-party SIP Server

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Jul 14th, 2009
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Hello all,

We are currently asked by a telcom to test functionality of Cisco IP Phone 7940/60 with their SIP Server SBG (Ericsson) in a LAB environment.

I was able to change the firmware from SCCP to SIP successfully (version P003-8-12-00)

The Phones are connected to an ADSL modem and routed to SIP Server.

We are experiencing two major problems and I would like to get your advice:

1. I was able to registered the phones to the SIP server, however they are keep sending registration requests (especially 7960). Please see the traces attached.

Phones IP address are:

2. Calls between phones from different vendors that are connected to the same server were successful in/out. The problem is with PSTN calls. Outside calls are working while incoming not. From the traces it seems that the devices drop the calls. Please note that other vendors' phones (plus Linksys SPA922 series) are working both in and out with PSTN network.

Also, both IP Phones request a TFTP server for their configuration file when they get rebooted. When the server is up it takes few seconds to finish reboot. However, if the server is down ( it takes up to 5 minutes to startup. Is there a way to stop them asking for a TFTP server?

Attached you will find configuration files and traces.

Thank you in advance,


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paolo bevilacqua Wed, 07/15/2009 - 12:15
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Cisco doesn't care about their phones used with third-party IP PBX, and the subject is rarely discussed here.


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