The TCP/IP-220 is a network adaptor that can be fitted to any CRC220 or CRC221 door controller module to provide TCP/IP data communications between the door controller and the PC hosting the Norpass3 network management software. The interface can support the connection of a further 31 door controllers via an RS485 bus so that they can be served by the same TCP/IP port, thereby enabling flexible use of the available cabling infrastructure. The fitting of a TCP/IP-220 adaptor is quick and simple and can be fitted to any of the door controllers on the system according to the availability of existing or planned data communications installations.