US Patent 9518408 Alternate backup entry for vehicles

A door latch system for doors of motor vehicles includes an input device such as a keypad and a backup electrical power supply to unlock the door latch in the event the primary power supply fails, thereby eliminating the need for a lock cylinder. The door latch system is configured to supply electrical power from the primary electrical power supply to unlock the latch upon receiving a signal from a mobile phone, and to supply electrical power from the backup electrical power supply to unlock the latch if an authorized code is input via the keypad.