Proximity Readers Tutorial

By Brian Rhodes, Published May 20, 2013, 12:00am EDT (Info+)

One of the most common credentials is also the most confusing. How exactly do proximity cards 'read' into an electronic access system? Despite being widely used by more than a half-dozen 'contactless credential' types, that these credentials use nothing more than a simple wave in front of a reader can discount just how complex the process is. In this note, we look at 'proximity credentials', how they work, and the technology behind them.

What is 'Prox'

'****' ** **** * ***** ******** offering **** ********** ******** ******, ** **** ** * **** to ******** * ***** ************* **** *********** **** *** **** ***** **, *** do *** ***** *** ******. *** individual **** ******* ** *** *********** differ, *** ***** '***********' **** *** the **** ******* ********** ** ************ and *** ******** ** *** **** basic **********.

Proximity *****

* *** ** *** **** ***** 'proximity' ***** ***:

  • *** *** ****: ***** ********** ** *** ****. Proliferation ** '*****' *** *** **** chips, ***** ** *************, *** ******* storage **** **** ******* ** **.** MHz.
  • **.** *** ****: ******* * ******* **********, *** quicker ******* *****, ******** ** ******* bits, *** ********* ****** ** ****** in ******* ****** ********** **** ***** 125 ***.
  • ******* ******: ******* *** ** (***'* ********* market), ********** * **.** *** ***** ****** build ** ******* ** ************* ****** standards.
  • ******/**********: ***** *********** ******* **** **** one '***********' **********, **** *** ******* 125k, **.***, ** ***** *********** **** chips **** *** ******* *****/******* *********.

**** ****** ***** ******** ******* ***** the **** *******, **** *** *** interchangeable. **** ********** ****, ********* *********** are ****/**** ** *** **** ***** way, *** *** ****** ** *** information **** ******* *******. ** ********** ignition *** ** ****** *** *** a ********* ******** ******* **** ** office **** ***, *** **** **** must ** ******** **** * **** to ****. ********, * ******* **** will *** ******** ** * *** kHz ******, *** **** *********** *** the **** *********.

*** ********** ** *** ********** ******* are ***** *** ********* ***********; **** allows '*********' **** *********** ** ***** on *** **** **** ******* ************ issues.

Resonant ****** ********

*** *** * ******* **** ** fob, **** ** ******** *******, *********** communicate **** ** *** *** ** 3 ****** ** ****? ********* ***** are "******* ****" ******** **** **** on **** ***** ****** ** ****** power ** *** **********. ** **'* core, ******** ****** ******** **** ****** voltages, ********** *********** *** * ***** radio *****, *** ********* ** ** antenna ******** **** * **** ** fob.

***** ******, *** ***** ***** ********** power **** * *** ************ ** be ****** ****** *** **********. *** a ******** ************* ** '******** ****** transfer', *** *** ***** **** ***** of ******* * ********* **** * microwave:

** *** **** ** **********, *** field ******* *** ***** *** ****** the **** *** ****** ** ** alight. *** ********* ***********, *** ***** energy ******** ** **** ******* *** tightly ********* **** *** ******** ********** of ******* *****, *** *** ********** method ***** *** ****, **** *** credential ****** ***** ** *** **** and *** **** ****** ********* *****.

Inside **** *****

*** '************' **** ********** ********** **** variations ** ***** ***** **********, ********** in *** ***** *****:

  • ******* ****:* ******* **** ****** *******, ********* 20' ** ****, ** ****** ****** the ********** *** **** ** * bidirectional *******, **** ********* (*** **********) the *********, *** **** ************ *** ICC ****'* *********** ** * ******.
  • *********:**** ********* ******, *** * ***** period, *** ****** ******* ** *** reader. **** *** ******** ** *** capacitor ** *******, ** ************** ********** into *** *** **** *** *** antenna.
  • *** ****:*** **** ****** *** *********** ********* by *** **********, ********* ******** ******* like ******** *****, ****** ** *******, and ***** ****** ******* ****** ** the ****. **** *********** ** ********* to *** ********* ****** *** *** Antenna ****.

* *** ************** ** **** ********** is *** *** ***** ************. ***** the ****** *********** ***** **** ******* human **********, ** ***** *** ********** must ** ********** ***** ** *** energy ****** - *** ******. **** describes *** '*********' **** **** ** mere ****** **** **** *** ****** in ***** ** ** *********:

** *** **** ** '**** *****' readers, *** **** ** *** **** is ******. ******* *** ***** ** the ****** ****** ** ********* ****** FCC ******* ******, *** ******** **** and *********** ** *** ******'* ******* must ** ******. * ******* ********* reader **** ******* ***** *" * 3" * *.*", * **** ***** to **** *********** ************* ** ** *'*** ******* **" * **" * 2".

Comments (2)

Brian, good intro and sorry for late reply. It may well be a good idea to discuss practical read range of 13.56M vs 125kHz (reader design) and application implications as well as overal security of RFID cards in system design.

With regard to later I always found it interesting that after 10 years from major introduction of 13.56Mhz products to market that nearly 50% of new sales (not cumulative) remain low frequency products even today. A nod to the long lifecycle of access systems.

Furthermore that nearly all low freq products use simple serial and even more interesting majority of high freq product use only CSN/UID!! What corp risk mgt doesn't know but maybe should about their system design and data security.

Thanks again.

Great article Brian. Learning more about the differences in Prox technologies, I'm not interested in customer responses to more informed questions

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