The external sound for the incoming calls are not geard

Hello srisailapathy and welcome to Apple Support Communities. It appears you are having some difficulty hearing phone calls on your iPhone. Start here:

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker

Cheers.

Hi srisailapathy.

Are you saying that others can't hear you when you are making a phone call but you can hear them? If that is the case, start with the tips in this article:

If the microphones on your iPhone, iPad, and iPod touch aren't working

If this is not the issue, please provide a detailed description of the exact issue. The more detail you can provide, the better the chances that someone in the community may be able to help out.

Cheers.