How Do I Add a 2nd Zone Expander to a VISTA-20P?

A user can connect a second 4219 Zone Expander to the VISTA-20P's ECP bus by wiring it in parallel with keypads, and ensuring the dip switches on the 4219 are properly set. They need to be set to address the 4219 as the second on the system. It will use zones 17 to 24, which is address 8.

The VISTA-20P system can support 8 hardwired security zones with the terminals on the main system board. The system can support an additional 40 hardwired zones with 4219 zone expanders. Each of these devices lets the system support an additional 8 hardwired zones. The 20P can have a maximum of (5) 4219 zone expanders on the system. Each of the zone expanders must have the dip switches on the unit configured so that the 4219 has the required address. The user should note that older generation models don't have the dip switch, so supervision is required. Below is a list showing the available addresses for the 4219:

Zone Expander Module & Zone Numbers

Dip Switch Address

Report Code

Module 1 for zones 09 - 16



Module 2 for zones 17 - 24



Module 3 for zones 25 - 32

09 (VISTA 20P)


Module 4 for zones 33 - 40

10 (VISTA 20P)


Module 5 for zones 41 - 48

11 (VISTA 20P)


If the zones on the 4219 are going to be supervised with resistors, the feature must be enabled on the unit. With dip switch 7 in the off position, the 4219 can work with or without with resistors. With dip switch 1 in the on position, the 4219 will work with a normal response time. Typically, the normal response setting will be used, as the fast response is only needed when the installation calls for it. With dip switch 8 in the off position, the 4219 case tamper switch will be enabled. If the cover for the unit is removed, it will send a trouble signal to the VISTA system.

To add a second zone expander to a VISTA-20P:

  1. Configure the dip switches. After setting the tamper, response, and resistor dip switches, the unit needs to be addressed. To set the 4219 to work as the second zone expander on the system, dip switches 2, 3, 4, and 6 need to be in the on position. Dip switch 5 will need to be in the off position.
  2. Wire the 4219 to the VISTA system. The 4 terminals on the right hand side of the 4219 connect the device to the ECP bus. The ECP bus makes up terminals 4, 5, 6, and 7 on the system. The 4219 terminals need to connect to the ECP terminals, via wire, or splice into wires connected to the ECP terminals.
  3. Wire the hardwired devices. Connect your data connections to the zone terminals, and power connections to the positive and negative power terminals on the 4219, routed to the 20P keypad bus. If the dip is set for supervision, then connect your resistors at the end of line. Make sure to install the 4219 tamper cover after completing the device wiring, if the tamper feature is enabled.
  4. Test the 4219. The security zones attached to the new 4219 should immediately function as normal security zones. If there are any problems with resistance, zone wiring, or the ECP wiring, the system will display a trouble. If a trouble does appear, go back to step 2 and check all of the wiring and the dip switches on the unit.

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