Simplex 4905-9938 SmartSync Control Module (SCM)The SmartSync Control Module (SCM) is designed to allow TrueAlert Non Addressable Horns, Strobes, A V, and S V units to be put on the same Notification Appliance Circuit. This allows the silencing of the Horns without deactivation of the Strobes. Use where SmartSync operation is required and is not available from the controlling NACs, or where Class A SmartSync is required.