tailieunhanh - The Cellular Connection 2 phần 4

Vì lý do này, cố gắng không để quay một số trong khi bạn đang di chuyển. Quay số có sự chú ý nhiều hơn bạn nghĩ, tâm trí, đôi mắt của bạn, và bàn tay được chuyển hướng từ kiểm soát chiếc xe của bạn. Các nhà thiết kế của điện thoại | The Cellular Connection A Guide to Cellular Telephones Fourth Edition. Robert A. Steuernagel Copyright 2000 John Wiley Sons Inc. ISBNs 0-471-31652-0 Paper 0-471-20340-8 Electronic GLOSSARY A Carrier The nonwireline carrier. See Nonwireline. A-B Switch A switch on a cellular phone that permits you to change between the A and B block carrier or make one a priority. Usually the carrier you subscribe to will set their block as priority on your phone. Usually only your dealer or carrier will need to change this setting. Access Charge The fixed monthly charge for cellular subscription. This may include an allowance of airtime usage as well as the use of special features like voice messaging in some carriers cite plans. AMPS An acronym used as the name for the current cellular standard used in the United States. It originally stood for Advanced Mobile Phone Service the name AT T chose for cellular service. The previous standard for mobile phone service for example had been called IMTS or Improved Mobile Telephone Service. Digital cellular standards like CDMA and TDMA are also part of the AMPS standard. Antenna A length of wire that radiates or captures radio signals. Area Code The first three digits of your phone number formerly the middle one of which was always 1 or 0 but now may be any digit that identify the geographic area of telephone service. The local calling area of your cellular service may include more than one area code. The area code is technically referred to as an NPA or Number Plan Area. 121 122 GLOSSARY Band A portion of the radio frequency spectrum. Cellular communications take place in the 800-MHz region of the UHF band while PCS is in the 1900-MHz area. Base Station A cell site. B Carrier The wireline carrier. See Wireline. Block A group of radio frequencies within a band set aside for a particular purpose. Cellular telephony uses four blocks of frequencies in the 800-MHz portion of the UHF band. A-block and B-block carriers are assigned separate .