Coding damper + mechanism. If a siren has a box where the intake is located it most likely is controlling a damper (via the use of a solenoid). Looking inside the intake can confirm this or not. A 3T22 for example has two of them to do the Hi-Lo or pulse signals.SilverThunder710YT wrote: ↑Wed Mar 15, 2023 5:14 pmHow can I even tell if a siren is coded? If you show me a coded P-10 and a normal one I assure you I won't see any difference