System BTS 4000 is an emergency telephone system without the requirement for any external power supply. All energy required for 4-6 minutes of continuous operation is produced by the call generator.
The system is equipped with a sophisticated, extremely low power amplifier with high power and low distortion output. The amplifier is integrated in one of the telephone units to reduce the installation cabling. The system may also be connected to 24 VDC power supply to ensure continuous operation under normal conditions. The system automatically switches to batteryless and emergency operation in case of mains failure.
The system is based on three types of units; 4050-single line (direct call), 4060-12 lines version and 4040-24 lines version. Any configuration needs one master telephone with a built-in amplifier, either 4051-single line or 4060-12 line version. For the 24 lines version a separate speech amplifier type 4000 is needed.