Choosing access control readers
Access control systems are designed primarily to regulate access to a building or certain area, while usually also permitting data to be collected about transiting users. The characteristics you envision for – and the tasks you will assign to your access system in turn will demand particular features from the RFID readers you will choose. These characteristics include interface, environmental tolerance, data protocol, identification technology, the readers’ ability to transact with other (e.g. mobile) devices and features for simplifying or streamlining their installation. Combined, all these factors will refine your options toward selecting the best reader for your system.
We frequently discuss the features outlined below when we help customers choose a reader for their planned systems.
Readers interact with your system via their interfaces. Your system might specify Clock & Data, Wiegand, USB, GPRS, RS232 or an RS485 interface, requiring a reader able to connect via that particular interface.
Data protocols like the standardized OSDP (either v1 or v2) or AES might also be indicated. Some customers prefer specifying their own protocol (which Idesco embeds in their readers) while others opt to use Idesco’s own RS485 data protocol. Note the OSDP and RS485 data protocols are bi-directional, permitting your system to send data ‘downstream’ to its readers – not merely receiving their transaction data from them. Such bi-directional data flow is a powerful capability because it can let you manage your readers from your system, simplifying updates in particular. By contrast, data transmitted via Clock & Data and Wiegand interfaces is unidirectional – only sent ‘upstream’ from a reader to its system.
Pay special attention to the identification technology you choose for your system because it can significantly limit your reader choice. By contrast, if you select an open, standardized technology like MIFARE® it will let you shop for readers from a wide range of manufacturers. Obviously, this also applies to sourcing users’ transponders.
Your choice of identification technology can also limit how secure your system will be. MIFARE DESFire is one of the world’s securest technologies, capable of deeply encrypting the data stream between readers and transponders. Depending on the data protocol or additional security solutions you deploy, that deep security can also be extended to data transmitted between readers and their host. Lastly, if readers will be identifying mobile device credentials in addition to traditional transponders, or you plan to migrate completely to mobile device transactions, your readers will need to support Bluetooth, NFC or a similar protocol, depending on the capabilities of your system’s and your users’ mobile devices.
Your system’s planned tasks could demand greater transaction bandwidth from its readers. In general, readers that support the latest technologies also offer such greater data bandwidth. Such transaction bandwidth (and greater transponder data capacity) is most often found in applications either storing additional data in transponders’ memory blocks (e.g. payment systems), or in more secure systems that use complex ‘handshake’ verification protocols to secure transactions with encrypted transponder credentials (as opposed to unsecured factory-coded UIDs).
Inputs and outputs
A reader installed in a system may have outputs that let it control other devices. Additionally, a reader’s inputs can let you, your system, or the reader’s host control a reader’s buzzer or LEDs. For some readers, their inputs and outputs let you configure them for ‘stand-alone mode’, which lets them control electrical locks independently, without a system connection.
Features related to reader’s installation
A reader can be shipped with either an attached cable, a connector or even a convenient, fast-installing adapter plate that significantly speeds and simplifies installation. If you thread wiring well in advance of actual reader installation, adapter plates not only let you install readers in phases but will significantly shorten installation time; you simply just push readers onto their plates then secure them with screws.
Durability and impact resistance
Installations can vary widely, from comfort-regulated indoor office environments to the harshest industrial or outdoor settings with extremes of heat, cold, sun, moisture, dirt, reactive chemicals – and vandalism. This diversity can place a wide range of demands on your system’s readers. Although manufacturers usually guarantee basic storage and operational temperature ranges for their products, if you know your site’s readers will be exposed to vandalism or extremes of temperature, moisture or dust, check reader ratings (i.e. IP protection class and IK impact resistance) before you choose.
For additional information, contact customer support.
How does RFID actually work, and what kind of features do transponders require to make it work? This article answers these questions by focusing on RFID’s transponders and their identification capability. If you are a system integrator, your own customers might find the points covered in this discussion helpful.