Kts definitions

A voice-optimized telecommunications system designed for small business or small office applications (see Figure K-1), typically defined as involving no more than 50 stations.The term key refers to the buttons that mechanically opened and closed the line circuits on the early generation of KTSs. Although the buttons are no longer mechanical keys, KTSs remain relatively simple CPE systems that allow multiple station users to share a number of outside lines that the users select by depressing the button associated with the specific circuits they desire to access.This approach is unlike that of a PBX switch, which has the intelligence to accept a call request from a user station, determine the most appropriate circuit from a shared pool of circuits, and set up the connection through common switching equipment. Most small KTSs are squared, meaning that every key set is configured alike, with every outside line appearing on every set. Thereby, every station user can access every outside line for both incoming and outgoing calls, and all feature presentations are consistent. In larger systems, the physical size of the telephone sets required to maintain the squaring convention would be impractical, but departmental subgroups often are squared.As illustrated in Figure K-1, all but the simplest key systems have a software-based common control unit, known as a Key Service Unit (KSU), where programmed features are stored and provided to individual users and stations based on their individual access privileges. Introduced in 1938, early Key Telephone sets electromechanical KTS systems (1A, 1A1, and 1A2) were limited in feature content to hold, intercom, speakerphones, and auto dialers. Electronic KTS (EKTS) systems appeared in the 1970s, offering many of the same features as PBX systems. Most contemporary key systems are hybrids, meaning that they can operate either as a KTS or a PBX. Hybrids generally are limited to 200