PRS‑CSRK is a PCB circuit board that functions exactly the same as the PRS‑CSR remote call station, but it has no shell and other related components. It is mainly used in custom applications. It connects one-on-one to the PRS‑CSI call station via the cat-5 cable, which is part of the Praesideo fiber network. The cat-5 cable is used to transmit digital audio and control data up to a kilometer. The length of the cat-5 cable is not part of the length of the Praesideo fiber optic network. Therefore, this greatly increases the total length of the optical fiber network. Prs-csr can be extended to include up to 16 keyboards (LBB 4432/00 or LBB 4434/00), each with eight programmable keys. You can also use PRS‑CSNKP as an extension. Basic function this call station has a connection for connecting a microphone to be monitored. The converters and voice filters improve clarity and prevent audio clipping. It also comes with a volume control for monitoring speakers and headphones. The call station activates the speaker when playing music or prerecording information. When connected to the headset, it replaces the microphone and speaker. The call station has its own DSP and can convert between analog and digital audio. Audio processing includes sensitivity adjustment, amplitude limit and parameter balance. The suite is connected to the prs-csi device via a cat-5 cable, which then connects it to the Praesideo fiber network. The longest cable cannot exceed 1 km. The call station gets power from the interface via the cat-5 cable, but the call station also has a local power interface to cope with extreme cases of excessive cable length and keyboard size. Through a serial communication link, a call station can connect up to 16 call station keypads. The call station will power these keyboards. Users can assign up to 224 priority levels to call stations. All configurations can be completed by the Praesideo network controller. Remote call stations are fully monitored and fault protection operations are supported. Even if the Praesideo network controller fails, the call station can still make emergency calls. Interconnection, external power input and control input, for calling station 2 road keyboard serial data and power interface, microphone, speakers, headphones, speaker/headset volume control, control input (PTT), three channel control output (for state LED lights) certificate and recognized safety conforms to the standard IEC 60065 / EN 60065 immunity EN 55103 ‑ 2 standard cooling conform to EN 55103-1 / FCC - 47 standard 15 part b