A switching system in which the phones have multiple buttons that permit the user to directly select incoming or outgoing lines Key systems can typically support fewer users than PBXs, and their features are more limited
A multiple line phone system with basic feature's and intercom Usually configured in a squared fashion (all lines on all sets) But some can be configured in a pooled environment to emulate small PBX's
Small telephone system where multiple exchange lines can be presented on each telephone Key systems usually use telephones/terminals that are exclusively designed for a particular system
A Key System is the equipment utilized to provide the features associated with key sets, including keysets, multipair cable, key service unit, and distribution frames
A telephone system which requires special handsets The Inter-Tel Axxess switch sold by MIMIC in common with virtually all other manufacturers switches has proprietary handsets, i e they can only be used with other switches from the same manufacturer if the full functionality associated with the switch is required POT handsets can normally be used with any switch, but will offer only the most basic functions ( top )