How to Determine What RFID Proximity Cards to Order

How to Determine What RFID Proximity Cards to Order

by Mike Boehm on November 01, 2022

Once you’ve determined that your organization would like to incorporate RFID proximity cards into its systems for access management and security purposes, it’s time to determine the specific type of proximity card you should order. When considering the options, you must first understand the frequency, format, and bits that suit your specific business needs. Not all RFID proximity cards are created equally. This guide will help you identify proximity card types that are right for your organization.

It’s critical to get it right the first time so your business doesn’t waste money and time. With this forethought, you can avoid the hassle of guessing and get your RFID journey started on the right foot.

Pre-Existing System

If your business already has a pre-existing RFID system, it’s much easier

How to identify RFID proximity cards with box labels

to determine what RFID proximity cards you need. Do you have any old boxes that your previous set of RFID cards arrived in? What type of RFID card readers or scanners are installed? What kind of access control system are you using?

If you don’t know where to get started, please reach out to our support team at 970-682-0765 or We’ll walk you through how to figure all these specifics out and may request you to send pictures of your readers, so we can determine exactly what system you have and, therefore, what cards you need.

Determining the Frequency

You should start by determining what frequency you need your RFID system to operate within. There are three frequency categories to choose from: low-frequency, high-frequency, and ultra-high frequency. It’s important to realize these frequency bands are not standardized, so that the ranges can vary as big, but the general frequency range is consistent.

Low-Frequency (LF)

Low-frequency RFID systems operate within the 30 kHz to 300 kHz range and can be read from 0.5 meters away from the reader. 125 kHz is the most common frequency. RFID proximity cards using this frequency range are best for the following use cases:

1.   Access Control Systems

The majority of access control systems use the LF range. These systems generally serve only one function, most commonly building access. If you want to secure your premises, requiring an RFID access card to enter secure areas, then low-frequency is the preferred choice. RFID proximity cards must be brought within a few inches of the card reader. A popular option for schools, dorms, residential buildings, commercial buildings, data centers, and any other area that should be protected from security risks.

The identification information stored within a 125 kHz card is not encrypted. These cards are very susceptible to cloning. All someone needs is a $30 card copier and access to the physical card. In most situations, there is little benefit for anyone to clone an RFID card, but for specific high-security environments, these kinds of cards do not offer enough security.

2.   Time Clock System

RFID proximity cards within the LF range are also commonly used for time clocks. A single RFID card assigned to an employee can be used for access control and tracking that employee’s time and attendance. Businesses can not only track when an employee moves through their secure areas (which doors and when) but also know when they are clocking in and out. The employee simply needs to wave the proximity card within a few inches of the RFID reader time clock to clock in or out.

High-Frequency (HF)

High-frequency RFID systems operate in the 3MHz to 30 MHZ range and can be read from a farther distance than LF cards. High-frequency bands are better suited for secure application because this band includes the NFC or near-field communication protocol. The NFC protocol, a global communication standard, operates at the 13.56 MHz frequency. NFC adds a security layer that is not present in low-frequency cards. HF RFID proximity cards can also be used for time clock systems and access control systems. RFID proximity cards using this frequency range are best for the following use cases:

1.   Sales/Retail

If your brand is interested in offering retail, discount, or loyalty cards to customers with RFID proximity card capabilities, the HF frequency is preferred. These types of cards have been used in grocery retailers for a few years now, but it’s growing in other areas of retail. Since this use case involves monetary payments, the added protections of the NFC protocol are very important. You’ll need to support this card with the correct reader in all your stores.

2.   Contactless Payment Cards

Many financial institutions, from credit card companies to banks, include contactless technology in all of their newly issued payment cards. This contactless technology is powered by RFID and NFC technology. These cards are inexpensive to manufacture and are popular among consumers because they are quick and easy to use.

Ultra High-Frequency (UHF)

Ultra-high-frequency and Super-high-frequency technologies have recently for RFID systems. UHF RFID solutions are usually in the form of tags for inventory tracking and asset management. There are few use cases for actual ‘cards.’ UHF solutions are best for situations that required ‘high-volume reading’ like inventory tracking in a warehouse.

Determining the Format

Determining the best format for your organization involves a bit more technical speak than determining the frequency. There are many formats to consider, especially proprietary formats that use their protocol. Let’s break down each format so you can choose the best option for your business:

Wiegand Format

The Wiegand format is one of the most popular formats for proximity cards and readers. The Wiegand format uses 26-bit encoding, but we’ll cover that in the following section. Wiegand readers are well-sealed and robust, performing in dirty or outside environments. But Wiegand readers require the card to be physically placed on the reader to communicate and verify the information.

Wiegand cards are readily available for access control systems in the form of Clamshell Clamshell Cards, Printable CR80 Cards, Printable CR80 Cards with Magnetic Stripes, and Inkjet Printable CR80 Cards.

Keri MS Format

The Keri MS proprietary format includes the KC-10X/KC-26X Standard Light Proximity Key Card, the MT-10X/MT-26X Multi-Technology Proximity Key Card, and other compatible cards.

The Standard Light card is a popular choice because it easily fits in a standard wallet, is highly durable, and is backed by a lifetime warranty. They have a vertical hanging slot and be imprinted through dye sublimation or lamination.

The Multi-Technology card allows your business to program a single card using several different identification technologies. The cards can be ordered with a magnetic stripe for retail use cases. These cards are generally only chosen when both magstripe and proximity use cases are required, because the Standard Light option is far cheaper and includes a lifetime warranty.

AWID Formats

The AWID format, another proprietary option, is a favorite within the security industry. AWID’s proximity cards offer better security in low, high, or ultra-high frequency options. These cards use the AWID protocol and can support 26-bit, 34-bit, and 50-bit.

DoorKing DK Prox Format

DoorKing Prox cards are proprietary cards that use the 26-bit format. DK Prox readers can read up to a 12-inch read range (1815-305) and can be mounted to meet your specific needs. The readers are sealed in epoxy so that they can serve in outdoor or indoor locations. These cards are primarily for access control but can also be implemented into traffic operators, gate operators, and other traffic control systems.


Indala proximity cards use the 26-bit format, also known as 40134. These cards are compatible with Indala 125 kHz proximity access control readers. These cards are programmable and offer outstanding stable performance. Essentially, unauthorized cards cannot send card data to the system.

HID 1326 Prox Card II

Perhaps the most widely used proximity card, the 1326 Prox Card II, is the global industry choice. The Prox Card II is compatible with all HID proximity card readers. These cards are durable and very price competitive. Each card has an external number, so system administrators can easily verify identification if needed. The HID 1326 Prox Card II supports up to 85 bits, allowing for 137 billion codes!

Determining the Bits

RFID proximity cards hold identifying information throught bit structures. Bit structures can range from 26-bit (the Wiegand format and the most common choice) up to 85-bits. Although most card formats only support one to three-bit formats. Determining the bits you need is about understanding how many unique identification cards your organization will need. Let’s take a look at some of the common bit formats, so you can make the best decision.


The 26-bit format is widely used within the industry, and most access control systems accept this card format. These are available as H10301 or 40134 (Indala) cards.

In the 26-bit Wiegand format, the card relays a series of 26 numbers in binary form. The first and last bits are not used when determining the card number but bits 2 through 9 are used to designate an 8-bit (0-255) facility code and bits 10 through 25 are used to designate a 16-bit (0-65545) ID number:

The 26-bit Wiegand format supports 65,545 possible ID numbers that you can assign within your access control system. That is 65,545 unique employees. The facility code is added to provide a higher level of designation across a business. If two businesses merge, some employees may have the same ID number but should have different facility codes, so there are no issues authenticating who is requesting access. The 8-bit facility code means there are 255 possible facility codes. Adding the facility codes means there is a total of 16,711,425 unique combinations of ID numbers and facility codes.


The 34-bit format works the exact same as the Wiegand format except there are 34 bits instead of 26. These proximity cards are also called the H10306 format. 34-bit systems have 65,545 unique ID numbers and 255 facility codes, meaning there are 16,711,425 unique combinations. This format is most commonly used for Honeywell and Northern Computers systems.


The 35-bit format supports 4,095 facility codes and 1,046,575 unique ID numbers. The HID Corporate 1000 proximity cards are the most common card type that uses 35-bit encoding.


The HID 37-bit H10302 Prox Card is the most popular choice for 37-bit encoding. This format supports 65,535 facility codes and 524,287 unique ID numbers. 


Getting Help from the Pros

If you’re still confused or want to consult an RFID professional to ensure you’ve decided on the right RFID proximity card for your business’s unique needs, please reach out. We offer world-class U.S.-based tech support and want to aid in adopting RFID technologies. We’re happy to discuss your best options or explain any technical specifications so you have a better understanding of RFID technology. 

Contact us at 970-682-0765 or

Free Samples

And if you think you’ve identified the proximity card type that is best for your organization, you can try the system out using our free samples. Sometimes during manufacturing or handling, cards get scratched or minimally damaged. Quality control removes these cards, so they aren’t shipped out to paying customers, but we keep these cards to offer as free samples.

We are happy to ship you free samples of the RFID proximity card product of your choice at no cost. We believe that the best way to help businesses choose RFID solutions is to reduce the barrier to entry however possible. If you have any issues setting up the RFID test cards or fobs, please call to receive support from one of our experienced techs.