Hello Naresh,
welcome to the Polycom Community.
The software you or your customer is using has not been supported for years so you should be looking at actually upgrading to a currently supported version.
The community's VoIP FAQ contains this post here:
Oct 7, 2011 Question: How can I setup my Phone / Provisioning / Download / Upgrade / Update / Downgrade Software?
Resolution: Please check => here <=
in addition you may want to look at this:
Oct 7, 2011 Question: Phone unable to send DTMF to an IVR system or how to troubleshoot DTMF issues
Resolution: Please check => here <=
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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The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.
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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
