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Prox Card Formats

Prox Card Formats

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The card format describes the data pattern programmed on your cards, and its compatibility with card readers.

How Prox Cards Work

All prox cards use a 125 kHZ frequency to transmit from the internal antenna embedded in the card to the card reader. However, there are multiple facility formats you may use.

Formats are like a language or code that the card is using to communicate with the reader. Not all readers can read the same format/language, so you need to make sure to order cards that are compatible with your reader.

Open and Proprietary Formats

There are both open formats and proprietary formats. Open format is most common and means that many manufactures can make and sell cards using that format.

Proprietary means protected – the reader only reads specific format that are only made and sold by a single manufacturer. This prevents customers from shopping around to buy generic cards that may be less expensive or easier to order than the proprietary cards.

This chart shows the most common format codes.

Card Format Facility Code Range Sequence Number Range Notes
26-bit H10301 0-255 0-65,535 Standard, most common format
26-Bit 40134 0-255 0-65,535 For Indala systems
32-bit N/A 0-1,073,741,823 Does not use a facility code
34-bit 0-255 0-65,535 For Honeywell/Northern Computers systems
35-bit 0-4,095 0-1,048,575
35-bit 0-4,095 0-1,048,575 For HID Corporate 1000 (must be registered)
36-bit 0-4,095 0-65,535 Legacy systems for HID Corporate 1000
37-bit H10302 N/A 0-34,357-738,367 For CardTrax program (must be registered), does not use facility code
37-bit H10304 0-65,535 0-524,287
40-bit 0-1,023 0-268,435,455 For smart cards only (doesn’t work with prox cards)
48-bit 0-1048575 0-1,048,575 For smart cards only (doesn’t work with prox cards)

How to Find Your Format Code

There are two easy ways to find your format code.

  1. Look at the label on your last box of cards – your format code will be listed there with your card information.
  2. Look at your access control software to see which formats it supports.

If you still aren’t sure which format you have, contact the experts at ProxSource.