Definition

• A key fob is an electronic version of a key. The cuts and grooves of old-fashioned metal keys allow them to fit into specific locks. By contrast, fobs use electronic codes that match the programming on specific locks.
  
  

Function

• Many people unlock their car doors from several feet away using a key fob attached to their key chain. This kind of key fob--also called a remote key--uses Radio Frequency Identification (RFID). The fob contains a silicone chip with an embedded antenna. When users press a button, the antenna transmits the code via radio signal. The lock contains a reader that receives the signal, determines the validity of the code and unlocks the door. Users can zap the code to the lock from an average of 50 feet away.
  
  To gain access to many apartment complexes or university facilities you may need a "proximity" key fob. Proximity key fobs also use RFID, however they must come within very close range to the appropriate reader device, generally mounted on or near the door.
  
  

Size

• A remote key fob for your car fits on your key ring or may even come attached to your ignition key. A proximity fob for a building door usually matches the dimensions of a typical key.
  
  

Safety Benefits

• According to the article "Replacing Car Keys is No Longer Quick or Cheap'" in the May 20, 2007 edition of "The Boston Globe" thieves cannot pick electronic locks, and many cars cannot start with the key fob out of range. Building security managers can also quickly deactivate key fobs without having to confiscate physical keys. And an article entitled "ECU Residence Halls Receive Updates" in the July 31, 2009 edition of The University of East Carolina's "Pieces of Eight" newspaper, noted that the new electronic locks on its renovated dormitories made it possible to deactivate keys or quickly lock down facilities.
  
  

Considerations

• Car key fobs can cost between $80 to $350 to replace if you lose them. For apartments or other building facilities, a backup generator prevents the electronic key system from locking out residents during a power failure.