In bigger key systems, calls usually go to the receptionist or attendant , who will then tell someone that he or she has a call on a particular line, often using the intercom to call one phone, or by making a paging announcement to several people, or throughout a large area. Incoming calls usually go to a receptionist, attendant or operator, who transfers the call to the appropriate person. Some telecom newbies say Key System Unit . Computer guys often call it a Central Processing Unit , or CPU . Old telecom guys call it a switch .
Cardiologists call it a heart .
Neurosurgeons call it a brain . It's OK to say dial, even if you make your calls by tapping buttons on a touch-tone pad. POT , on the other hand, is not a plain old telephone. The story of the octothorpe and other vital telecom info is available in the archives of Telecom Digest . The asterisk under the 7 and to the left of the 0, is called Star.