Révisi nurutkeun 26 Pébruari 2008 05.22 édit Hadiyana (obrolan \| kontribusi) 3.120 suntingan →‎Téknologi: saeutik nuluykeun tarjamahan ← Éditan saméméhna		Révisi nurutkeun 26 Pébruari 2008 09.06 édit bolaykeun Hadiyana (obrolan \| kontribusi) 3.120 suntingan ngeureuyeuh saeutik nuluykeun hanca tarjamahan sanajan sibuk Éditan salajengna →
Baris ka-8: Nu ngabédakeun AMPS ti téknologi lianna nu leuwih kolot nyaéta ayana "back end" ''call setup functionality''. Dina AMPS, puseur-puseur sél bisa sacara fléksibel méré kanal kana ''handset'' dumasar kana kuatna sinyal nu dipancarkeun ku ''handset'', temahna frékuénsi nu sarua bisa digunakeun deui di patempatan lianna tanpa ngakibatkeun gangguan. Temahna, AMPS bisa ngaladénan réa nomer langganan dina wilayah tinangtu. AMPS jadi panaratas istilah "sélulér" lantaran ieu téknologi nu munggaran ngagunakeun sél-sél héksagonal nu leutik dina sahiji sistem. <ref name="bell_young">W. Rae Young, "AMPS: Introduction, Background, and Objectives", Bell System Technical Journal, vol. 58, 1, pages 1-14, January 1979. ''(Note: Young was the Bell Labs engineer who invented the hexagonal cell concept.)''</ref><ref name="bell_porter">Z. C. Fluhr and Philip T. Porter, "AMPS: Control Architecture", Bell System Technical Journal, vol. 58, 1, pages 1-14, January 1979. ''(Note: Porter was the Bell Labs engineer who proposed that the cell towers be at the corners of the hexagons rather than the centers and have directional antennas that would transmit/receive in 3 directions into 3 adjacent hexagon cells.)''</ref> Aya sawatara kakurang AMPS lamun dibandingkeun jeung ~~teknologi~~téknologi digital kiwari. Lantaran ieu ~~teknologi~~téknologi sifatna analog, AMPS uduh pisan ku gangguan statik jeung nois sarta teu boga panyalindungan tina ''panguping'' (basa Indonesia: penyadap) sora nu ngagunakeun [[Scanner (radio)\|scanner]]. ~~{{tarjamahkeun\|Inggris}}~~Dina taun 1990-an, "cloning" ngarupakeun panyakit épidemik nu ngarugikeun industri telekomunikasi trilyunan dolar. ''Penyadap'' nu teu jujur ieu kalayan ngagunakeun alat husus bisa nguping (nyadap) nomer seri éléktronik ([[ESN]]) dina jero ''handset''. ESN téh ngarupakeun pakét data nu dikirim ku ''handset'' ka koropak langganan dina sistem sélulér nu dimaksudkeun pikeun ngumpulkeun data tagihan. Sistem sélulér satuluyna ngabeunangkeun atawa ngalarang pamaké ''handset'' pikeun nelepon atawa ngagunakeun fitur tinangtu dumasar kana koropak langganan kasebut. Lamun ESN disadap, mangka nomer kasebut bisa ditiron (di-cloning) ku telepon lianna sarta digunakeun di daérah lian pikeun nelepon tanpa mayar. Sanajan ''cloning'' masih bisa dilakukeun kiwari dina jaman téknologi digital, saeutik pisan untungna sahingga masalah ieu leungit sorangan. Kiwari AMPS geus kasilih ku standar digital nu leuwih anyar saperti [[D-AMPS]], [[GSM]], jeung [[CDMA2000]] nu nawarkeun kaamanan nu leuwih hadé sarta kamampuh nu leuwih gedé. In the 1990s, "cloning" was an epidemic that cost the industry millions of dollars. An unscrupulous eavesdropper with specialized equipment can intercept a handset's [[Electronic Serial Number\|ESN]] (Electronic Serial Number). A Electronic Serial Number is a packet of data which is sent by the handset to the cellular system for billing purposes. The system then allows or disallows calls and or features based on its customer file. If an ESN is intercepted, it could then be cloned onto a different phone and used in other areas for making calls without paying. The problem became so large that some carriers required the use of a [[Personal identification number\|PIN]] before making calls. Though cloning is still possible even with digital technologies, the cost of wireless service is so low that the problem has virtually disappeared. AMPS has been replaced by newer digital standards, such as [[Digital AMPS]], [[GSM]], and [[CDMA2000]] which brought improved security as well as increased capacity. ~~AMPS was originally standardized by ANSI as EIA/TIA/IS-3. This was later superseded by EIA/TIA-553 and TIA interim standard IS-91.~~ ==Pita frékuénsi== {{tarjamahkeun\|Inggris}} AMPS cellular service operates in the 800 [[MHz]] [[Cellular frequencies\|Cellular]] [[FM]] band. For each market area, the United States [[Federal Communications Commission]] (FCC) allowed two licensee (networks) known as "A" and "B" carriers. Each carrier within a market uses a specified "block" of frequencies consisting of 21 control channels and 395 voice channels. Originally, the B (wireline) side license was usually owned by the local phone company such as a "Baby Bell" (Ameritech), and the A (non-wireline) license was made available to private companies such as Cellular One. At the inception of cellular in 1983, the FCC had granted each carrier within a market 333 channels (666 channels total). By the late 1980s, the cellular industry's subscriber base had grown into the millions across America and it became necessary to add channels for additional capacity. In 1989, the FCC granted carriers an expansion from the current 666 channels to the now 832 (416 per carrier). The additional frequency was available in the upper 800 MHz band which also was home to UHF channels 70–83. This meant that these UHF channels could no longer be used for UHF TV transmission as these frequencies were to be used for AMPS transmission.

AMPS: Béda antarrépisi