Interrnal sounders are a useful addition to any alarm system. They almost certainly prevent intruders from spending more time than is necessary in the premises.
Internal Extension Speakers
The majority of Stand-alone control panels have a speaker fitted in the panel. This speaker serves both as a low volume entry/exit sounder and a high volume alarm sounder. This speaker can be moved from inside the control panel to a remote location or additional extension speakers can be fitted remotely. Extension speakers will replicate the internal speaker sounds.
Internal Piezo Sounders
Internal Piezo sounders are connected across the bell output and replicate the external sounder sounds. Internal Piezo sounders are also available fitted with SAB modules which operate exactly as the external sounder.