You can always contact me by phone. I will always be ready to talk with you and come to you if you ask.

"I am a phone call away" means that although there may be a large physical distance between two people, if they talk to each other over the phone it will be as if they were close again. The person who says "I am a phone call away" is inviting you to call them any time for any reason, and they will be there:)

it means I am always available for u on phone,anytime u can call me.