System Sensor MDL3R


Sync-circuit module, 12/24 volt, red

Availability: In Stock

  • Factory New
Brand: System Sensor Part #: 31577 Category: Manufacturer Part #: MDL3RSecondary Part #: 20-1489


The Sync-Circuit module synchronizes SpectrAlert® Advance strobes at 1 Hz and horns and chimes at temporal 3 over a single pair of wires. Patented module technology also allows the silencing of horns or chimes on horn/strobe and chime/strobe models over a pair of wires.

The MDL3 Module is designed to work with the SpectrAlert and SpectrAlert Advance series of notification appliances to provide a means of synchronizing the temporal-coded horns and chimes, synchronizing the one-second flash timing of the strobe, and silencing the horns and chimes of the horn/strobe and chime/ strobes combination over a two-wire circuit while leaving the strobes active. Application Flexibility.

The Sync-Circuit module is designed to power and synchronize either two 3-amp circuits wired in Class B, or one 3-amp circuit powered as Class A. Should more than two zones require synchronization, additional modules can be added by interconnecting the “slave” input and output terminals between modules.


Weight 0.40 lbs
Dimensions 1.00 × 5.25 × 5.25 in






System Sensor

Production Status



  • Two-wire operation from module to the devices
  • Silences horns and chimes over a two-wire loop
  • Synchronizes strobes at 1 Hz
  • Synchronizes horns and chimes to temporal 3 pattern
  • Patented technology
  • Interconnects modules for multiple zone synchronization
  • Module controls two Style Y (Class B) circuits or one Style Z (Class A) circuit
  • New NAC slave feature enables the interconnection of slave modules over a supervised NAC loop

Sync•Circuit Module


System Sensor - Data Sheet

MDL3 Series Sync Module


System Sensor - Installation and Maintenance Instructions