Labels:text | diagram | black and white | font OCR: HOW IT WORKS There are two basic types of telephone offices thru which all calls are switched. The first is the CO, or Central Office. The wires from your telephone go LOS ANGELES NEW YORK to your local CO. From there your call is switched AREA 213 AREA 212 to another telephone in the same CO, meaning a local call, or it is switched to a toll office. A toll of - TOLL TOLI fice, for our purposes, is an "inter-office" office. The toll office connects different CO's to each SENDER When you dial a call from your phone, and suppose it other. SENDER happens to be long distance, the digits you dial, whether they are touchtone or dial type pulses, are sent directly to your central office. Most CO's have CAMA, Centralized automatic message accounting. The CAMA machine in the CO records your number, ...
