16 to 22), access control systems have embraced structured cabling and Ether-
net for system controllers and the centralized server.
In addition, the requirement for the system to share databases with business
systems has pushed the marketplace into offering databases that are compliant
with SQL and ODBC standards.
IP POE-Powered Access Control Systems
Access control systems that incorporate IP and power-over-Ethernet (POE)
components have been introduced to the marketplace in recent years. The evolu-
tion of access control systems to structured cabling, IP protocols, and POE was
inevitable; a similar evolution took place in telephone and video surveillance sys-
tems. This transformation leverages the existing IT infrastructure, eliminates the
need for local power, consolidates and saves labor costs for cable installation,
reduces the time to install system devices, is more scalable and provides a large
base of management tools and support. The move is subtly but surely changing
the design and deployment of access control systems (Fig. 6.3).
In IP-based systems there is a direct network connection to either the door
controller or the card reader with the network connection providing low-volt-
age power. If the network connection is to the door controller, POE powers
the door contact, the lock, and the card reader. The door controller is really
a gateway at the edge of the IP network converting the data and protocols
from the door devices to an IP format. It has characteristics of typical door
controllers such as the capability to buffer events or cache access credentials
and features that address reliability and network performance issues.
If the IP access control system does not use a door controller, the network is
connected directly to the card reader and the card reader powers the door con-
tact and the lock. This approach not only eliminates the separate power
supplies but also the door controller (Fig. 6.4).
POE Power Issues
Some of the benefits and design issues with IP access control involve the elimi-
nation of high-voltage power and the use of POE. They are as follows.
Power Backup
In a traditional system backup power to door devices involves batteries and/or
high-voltage circuits above each door on emergency power. In an IP-access
control system if the network switches in the telecom rooms powering the IP
Access Control Systems 75