The TM detector unit is capable of protecting areas of up to 400 square meters even under challenging environmental conditions. Potential application areas include hotels, small server rooms and small high-rise warehouses.

The complete 420 Series provides three models, all specially designed to interface with the Bosch Modular Fire Panel 5000 Series with the extended features of LSN improved technology (Local Security Network).

Bosch's LSN bus system uses the master-slave principle, with all smoke detectors, remote indicators, fire alarm devices, intrusion detectors, keypads, arming devices and sounders connected to it. The network can be flexibly structured with loop, stub or tee-off configurations; the possibilities are additionally extended by interfaces with inputs and outputs and zone expanders. Power and data are transmitted over two wires. 'LSN improved' technology and modules accommodate currents up to 1,500 mA at distances up to 3,000 meters.

Smoke aspiration systems take air samples from the monitoring area through a pipe system with defined air sampling openings and pass the samples to the Aspirating Smoke Detector. The air is channeled through a detection chamber that has been specially developed for applications of this kind. In the detection chamber, extremely sensitive sensors ensure very early warning to provide sufficient time to extinguish a fire or take other necessary action.

Depending on the response sensitivity of the module, the Aspirating Smoke Detector triggers an alarm when the appropriate smoke density is reached. This alarm is displayed on the unit and is also transmitted to the fire panel.

An airflow sensor checks the connected pipe system for breakage and obstruction, and an intelligent signal processor compares the measured smoke level with known disturbance variables (such as dust, drafts and electrical interference) to determine whether an alarm is real or false. This allows for very high sensitivity and ensures reliable operation even in challenging situations with high ceilings, extreme temperatures, dirt or moisture. In addition, all products of the 420 series use a High-Power Light Source (HPLS) which makes the detection modules much more sensitive than conventional detectors.