What Does a Security System Zone Expander Do?

Many security systems have a small number of terminals on the main security board. Using the VISTA-21IP as our example, the system can interface 8 hardwired zones on the system but supports up to 48. The 4219 zone expander lets the system interface with an additional 8 hardwired zones.

The Honeywell VISTA 21IP has room to land 8 individual hard wired zones to the main security system. The system board has terminals with set screws that the security zone wiring connects to. The system does have room for an additional 40 zones in system programming. These zones can be wired or wireless. The 4219 zone expander is a device that has terminals for 8 hardwired zones. The 4219 connects to the VISTA 21IP via its ECP bus. This bus is located on the main VISTA system board from terminals 4 to 7. Terminal 4 is negative power, terminal 5 is positive power, terminal 6 is data in and terminal 7 is data out. The right side of the 4219 has terminals to connect to the ECP bus. Data in on the panel connects to data out on the expander and vice versa for data out on the panel.

The 4219 supports normally closed security zones. It will not support life safety devices such as smoke, heat or carbon monoxide detectors. The newer 4219 models have a dip switch to disable end of line resistor supervision. The older models don’t have this feature and require a resistor in the circuit. If you want to use hardwired sensors on all 48 security zones on the system, (5) 4219 zone expanders can be installed. Each 4219 will get addressed using the dip switches. For example, address 7 assigns the expander to zones 9 through 16. Each address assigns the module to the next 8 zones.

The VISTA 21IP also supports wireless devices. After a compatible wireless receiver is installed, the system can interface with 5800 wireless devices. Wireless devices can be programmed into any zone except for the 8 hardwired zones dedicated for the panel zone terminals. Wireless devices and the 4219 can work simultaneously as long as there is room in zone programming. Wireless devices cannot be programmed to any zone with out an 8 zone slot that is addressed by a zone expander. Even if that particular zone is not in use on the expander.