Retrofitting Access Control

Access control once deployed keys and keypads with codes. All that changed when the magnetic-stripe card hit the streets and it’s been up and away ever since. Now, access control is making the move to proximity, often referred to as hands-free, but is more appropriately called touchless access control.

The traditional magnetic-stripe card has changed. It’s become smarter, often incorporating other technologies such as proximity. But lately, because of widespread technological developments and price drops, proximity is emerging as the hottest technology around. With proximity, users simply move the reading device near the reader to gain access—if they are permitted.

For the electrical contractor, it’s the perfect time to upgrade access control to proximity or even biometrics.

Paul Chandler, product manager for Secura Key in Chatsworth, Calif., said making the move to proximity is not difficult with the right base.

“Most access-control systems today use the Wiegand data protocol to communicate between the reader/front end and the control system. Some manufacturers use a proprietary communications protocol that forces you to use their readers with their controllers,” Chandler said. “When this is the case, upgrade is much more difficult, involving replacement of everything but the locks and the cable.”

“When the host system is designed to accept a Wiegand input, there are numerous long-range card reader and biometric options available that allow you to leave the ‘head end’ in place,” Chandler added.

John Otters, technical support manager for HID Corporation, Irvine, Calif., agreed that the switch can be relatively painless with a little forethought.

“The upgrade to proximity is easy. Most access-control systems accept Wiegand or magnetic-stripe data input, so the switch to proximity from swipe technologies is easy. Wiegand is the most widely used data protocol. Manufacturers may also offer readers that interface with the system through a variety of data protocols, including Wiegand, clock and data (mag stripe) and various serial protocols for direct input into computer-based applications,” Otters said. “Biometric readers typically validate the user’s biometric template locally, then transmit the user-card data after confirmation that the biometric matches the cardholder. The access-control system sees the Wiegand card data instead of having to process biometric templates.”

Otters said most access-control systems have the hardware and software in place to process Wiegand data. In the maturing access-control market, manufacturers have put a priority on system flexibility and compatibility with new technologies.

“The usual upgrade route is to replace existing access-control cards and readers with the new technology products. Older access-control systems don’t necessarily have to be replaced, but may be upgraded to take advantage of new features or performance, much like upgrading an older PC,” Otters added.

One of the important questions to explore, according to Secura Key’s Chandler, is how the Wiegand data is formatted.

“The most-common format is 26-bit Wiegand. This format includes 16 bits for card identification, eight bits for facility code and two parity bits. Many other formats can be created and some control systems require special formats. Where this is the case, it requires new readers capable of handling the custom Wiegand format and new cards with data in that format,” Chandler said.

He added that when retrofitting biometric readers there will often be the need to run extra wires to each reader site to allow the central enrollment of users and download user templates to reader stations.

The decision to leave the old head-end system and simply replace the front-end readers or biometrics is a complex one. On the one hand, new control systems are generally more versatile and easier to work with. Newer software is more likely to be truly Windows-based, more intuitive and able to run on newer operating systems.

On the other hand, the main reasons for keeping the old control system are cost and short-term convenience. Transferring data and programming from an old system to a new one can be cumbersome. New software will almost always mean new field control panels and possibly new cabling.

O’MARA is the president of DLO Communications in Park Ridge, Ill., specializing in low-voltage. She can be reached at 847.384.1916 or

About the Author

Deborah L. O'Mara

Freelance Writer
Deborah L. O’Mara is a journalist with more than two decades experience writing about security, life safety and systems integration, and she is the managing director of DLO Communications in Chicago. She can be reached at

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