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Cross over of voice calls on Ericsson MD110

How can you stop cross over of voice calls when using the Ericsson MD110 linked via a 54mb wireless link into an Ericsson BP250? Get configuration advice in this expert response..

Does anyone know why we are experiencing "cross over" of voice calls when using the Ericsson MD110 linked via a 54mb wireless link into an Ericsson BP250? Example user A & B are based at the BP250 site and users C & D are based at the MD110 site. User A dials user C and B dials user D. User C hears the conversation of user A but also clippings of what user B says...the same with user D. All remote users hear segments of other conversations.
It is likely that the configuration is something like the following:<.br>

MD110<-TDM->PSTN to IP gateway<- Wired Ethernet->Wireless Gateway<-Wireless->Wireless Gateway<-Wired Ethernet->IP to PSTN gateway <-PCM->BP250.

When a voice conversation is converted into IP there are two speech streams transported by RTP. In the example given there are 4 streams for the two conversations. The first goal is to figure out where this 'cross talk' occurs. The best way is to use a network sniffer on the wired Ethernet and wireless sections and capture the RTP streams at each point. A couple good analyzers are Ethereal http://www.ethereal.com and the one from Clearsight networks .

After performing this analysis, you should be able to figure out if the problem is with the wireless devices or the PSTN gateways. It is unlikely a configuration problem. It is more likely a bug in the software of one of the devices that is causing the problem.

This was last published in August 2005

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