For fire and safety reasons, and per building code in many jurisdictions, a Request to Exit (REX) device is used to ensure free egress. It is always important to defer to the Authority Having Jurisdiction (AHJ) for all building code requirements, including code requirements for REX devices and how they should connect to an access control system, such as Avigilon Alta. 

Although you can wire a REX directly to the Avigilon Alta (formerly Openpath) ACU like most other access control systems, the best practice would be to wire the REX in series with maglock or other fail-safe hardware. This prevents any points of failure in the egress path.  If the REX device is wired directly to the REX input on an ACU, then Avigilon Alta can simply shunt forced open alarms only, or shunt forced open alarms and also trigger the relay to unlock. In the event that there is complete power loss, then the lock hardware specified by the AHJ would be Fail-Safe or Fail-Secure.

• Fail-Safe - When power is lost, the door will result in an unsecured position (unlocked). 

• Fail-Secure - When power is lost, the door will result in a secured position (locked). 
  

REX with Video Reader Pro and Video Intercom Reader Pro

Since these devices do not contain a REX input you can use a remote ACU to manage door peripherals, such as a door lock relay, door contact, and a REX device. A LAN connection to the remote ACU is required to control all door peripherals that have been assigned to the Video Reader Pro or Video Intercom Reader Pro entry. We have found in some cases the Video Reader Pro and the Video Intercom Reader Pro go offline, and if the REX is not wired in a series with the lock hardware, the REX on the entry does not engage the remote relay. It is important to follow the best practices outlined in this article and the diagrams below in order to ensure a reliable experience when the Video Reader Pro or Video Intercom Reader Pro is inaccessible due to a network interruption, maintenance, or firmware update.

Example 1: Remote REX on SDC with Video Reader Pro / Video Intercom Reader Pro

Example 2: Remote REX on OP-EX-4E with Video Reader Pro / Video Intercom Reader Pro

To further improve reliability, Avigilon Alta will be implementing changes that will engage the remote relay for the entry when the REX is triggered even if the associated video device is unavailable. The controller for this relay should have a battery backup or be wired in a fail-safe configuration for maximum reliability.

Note that in the reporting, a REX event on Video Reader Pro and Video Intercom Reader Pro entries will appear twice due to these changes. This duplicate can be safely ignored.