Choosing a wireless electronic access control solution

An overview of the advantages of both networked and standalone systems

The reader is incorporated into the door handle/release mechanism, allowing the door mechanism to control access as well as limit access to authorized cardholders only. The door mechanism can also time stamp the cards that were allowed and denied since the last communication with the data-gathering panel.

The wireless communication from the reader to the data-gathering panel can be 802.11, which would be ideal for an IP-based electronic access control system. This communication can also be encrypted.

In the IP-based architecture, a WiFi node would communicate to the door reader/mechanism and then communicate to a central computer. The wireless door reader/mechanism is based on open architecture, using the existing network standard.

The advantage to this system is its ability to connect to an existing WiFi network. For this type of application to work well for the Security department, a solid working relationship would need to exist or be developed with the Information Technology (IT) department.

In the data-gathering panel example above, the door reader mechanism could communicate to an RF receiver that would connect to the data-gathering panel. This approach could use a WiFi receiver or a radio receiver on another frequency; however, a protocol must exist that allows the data-gathering panel to understand the data it receives from the door reader/mechanism. Many door reader/mechanism manufacturers have made agreements with the manufacturers of electronic access control systems that incorporate data-gathering panels to allow proper communications. The actual card data is normally Weigand protocol, but the other communications required to process and modify the memory within the door reader/mechanism will be proprietary to the data-gathering manufacturer.

A final advantage of a networked wireless electronic access control system is that the door reader/mechanism can operate in a standalone mode until communications is desired or reestablished, if lost. The communication is normally "real-time" or on a set interval. The door reader/mechanism uses battery backup to enable transmissions to a receiver either at the data-gathering panel or on a WiFi node while retaining the access transactions on a FIFO memory located in the door reader/mechanism. The battery backup is in the form of commercially available standard configuration batteries, such as AA (6ea.). The electronics in the door reader/mechanism is designed for minimal current draw, thus allowing batteries to last an extended period of time. The actual battery life will depend upon the number of door releases, communications back to the data gathering panel/WIFI node and updates from the central computer. A rough time estimate for battery life would be in the 18-month range for a door reader/mechanism with "average" usage.

The door reader/mechanism also reports battery status back through the receiver to notify maintenance personnel of its status. The battery replacement usually requires a special type of wrench and access to the secure side of the protected area. In high-traffic areas, a power supply can be added to eliminate any battery replacement issues (requires some additional wiring).

Standalone Wireless Access Control

In a standalone wireless access control system, each portal or door is controlled by a door reader/mechanism that can hold many card numbers and can store transactions, similar to the centralized/network door reader/mechanisms discussed earlier. The primary difference is that the standalone reader does not communicate to a data-gathering panel or WiFi node. This unit will transmit the transactions and modify card numbers via a wireless link directly to a computer in close proximity to the reader; or, it can sometimes modify the user card numbers with specially coded cards.

The advantage of a standalone system is that it can be installed virtually anywhere without regard to communication infrastructure. Remote sites or retrofits are ideal applications for this type of system. The door reader/mechanism is installed, updated and put into operation and can be left alone except when an access/denial report is desired or when card numbers need to be added or deleted in the device. The door reader/mechanism normally replaces the existing lock and key hardware.