A phone embedded within a vehicle for automatically using a service plan of a proximate personal mobile phone. The embedded phone includes an internal communication component that detects the presence of the personal mobile phone, and receives a mobile subscriber identification number from the detected phone. The embedded phone also includes an external communication component that sends the received mobile subscriber identification number to a wireless network authority, and receives an authentication request to the personal mobile phone via the embedded phone. The internal communication component sends the authentication request to the personal mobile phone. The personal mobile phone generates an authentication signal, and the external communication component sends the authentication signal to the wireless network authority.