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Microsoft Roundtable and Nortel BCM50 - no dial tone

Occasional Visitor

Microsoft Roundtable and Nortel BCM50 - no dial tone



We are having problems connecting a Microsoft Roundtable (Polycom CX5000) unit to our Nortel BCM50 PBX.


The Roundtable's phone line icon shows as on/available when the phone cable is plugged in, but there is no dial tone and we are unable to dial/call either internal extensions or outside numbers.


The current Nortel handset plugged into the same port works fine, so it does not seem to be the port, cable or RJ11 to RJ45 adapter.


Even so, we have changed ports, cables, RJ11 to RJ45 adapters, etc - all to no avail.


I have also reset, updated and reconfigured the Roundtable unit a few times, all with the same result.


Can anyone help shed any light on this - or is the Rountable incompatible with the BCM50 or maybe just faulty?


Many thanks,


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Polycom Employee & Community Manager

Re: Microsoft Roundtable and Nortel BCM50 - no dial tone

Hello Steve,

welcome to the Polycom Community.

The Polycom CX5000 telephony functionality is for an analog line only. 


I can only assume that the PABX you are using is either digital proprietary Nortel or IP based.

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

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Message 2 of 2