– 2 –CENTRAL OFFICE CALLA call sent to a business from the external network.LOOP KEYKeys on the console that are designated to ring and flash when a call is sent to the console. These calls are usu-ally from the central office. The term “loop” refers to the wires that run from a central office to a customersite.NEAX®2400 IPXThe entire NEC telephone system, including the system’s central processor, lines, telephones and the console.STATIONA telephone that is part of the NEAX 2400 IPX and has an extension number assigned. Calls from a stationare considered internal calls for the purposes of this guide.TRUNKA telephone line that connects a customer telephone system to the external telephone network.