SAMSUNGDCS-816 Installation Manual2-72.7 SELECTING OPTIONS ON THE BASIC KSU (Figure 2-5)There are some hardware options to select in the basic KSU: Memory Backup Selection, MusicSource Selection and MPD/PRS selection for the two (2) analogue trunk lines on the base board.2.7.1 Memory Backup SelectionThe system is equipped with 256Kbyte of data memory and memory backup circuitry (a super ca-pacitor) to protect the data in case of any power failure. The memory backup circuitry has a shunt-pin switch to enable backup. Before shipment, the switch is set OFF to prevent the super capaci-tor from discharging during shipment and storage, and it should be switched ON after installing andprogramming the system. Otherwise, the customer data and the programmed data will be lost inthe event of a power failure. (See Figure 2-5.)2.7.2 Music Source SelectionThe Basic KSU is equipped with a melody chip to provide music to stations and trunk lines as Mu-sic-on-Hold or Background Music. In addition, it has an interface for an external music source,(CD player, radio etc).As the system provides only a single music channel for Music-on-Hold or Background Music, referto Figure 2-5 to select the music source at the end of installation. A shunt-pin switch selects themusic source: the internal melody chip or an external music source.How to connect the external music source is explained in Part 7 of this manual, Connecting Op-tional Equipment.2.7.3 MPD/ PRS Selection and InstallationThe basic KSU has two (2) analogue trunk interfaces and each trunk interface is equipped with asocket to install an option chip for Metering Pulse Detection (MPD) or Polarity Reverse Signal(PRS) detection. (See Figure 2-5 for the position of option chip sockets and ensure that the chipsare firmly inserted into the sockets.) One chip per line. DCS option chips for MPD or PRS can beinstalled.Contact your dealer for details.