Nokia 6210
MODEM is not responding

Dear Sir,

In my project work i am using Nokia 6210 model mobile which has an internal Modem built. Also i know Model 6210 responds to AT Commands through hyperterminal. But when i am trying some AT Commands it is not responding. When i tried to Query Modem it is asking me to verify the modem is properly connected. What might be the problem for this?

Please sort me this issue.

Thank you.