... Plug off the power adaptor, Put the siren back switch to SIREN, then plug the adaptor after 2 seconds2 ... 4. When the alarm system alarms, the wireless siren would sound, and when the panel stops, it ... sensor to make it transmit a code. The siren would sound once after receiving the code. ... times means the numbers of registered wireless detectorsthe siren comes with 9v backup battery, able to standby ...