Wireless Alphabet Soup:What it All Means
CDMA, TDMA, GSM, iDEN, and AMPS, what do they all mean? Since you found this article you likely know that these are acronyms that primarily relate to the cellular phone industry, and this particular alphabet soup of acronyms refers to most of the wireless protocols that are used in the United States. What I will try to do is break down the different protocols into layman's terms starting with AMPS.
Wireless protocols are essentially the methods by which wireless, or cellular, signals are transmitted between a caller and a receiver. An easy way to follow the progression of these technologies is to start at the beginning and work our way throught them in chronological order. AMPS, commonly referred to as Analog, stands for Advanced Mobile Phone System and it was the name given original mobile phone system introduced to the U.S. in 1984. AMPS was a product of Bell Labs, and while analog is no longer considered remotely advanced (AMPS phones are the size of cinder blocks), the cellular switching technology AMPS introduced was cutting edge at the time.
AMPS uses FDMA, or Frequency Division Multiple Access, which is a ten dollar way of saying that each conversation is divided by assigning them separate channels. AMPS made this work better than past technologies were able to by computerizing frequency management, handset transmitter power, and call setup. Are your eyes beginning to glaze over yet?
AMPS was in wide us in the United States from 1984 to the late 1990's, though it did began to get supplanted by an early digital protocol, TDMA or D-AMPS. The writing was on the wall in the early 1990's when phone cloning (c'mon you remember cloning don't you?) became widespread. This was a scheme where unscrupulous individuals could fish AMPS cellular identification pretty much right out of the air and with a little programming create a second phone line that billed to the one they copied. On top of this, as wireless service was permeating the U.S. market the limitations of AMPS (assigning a whole channel to one conversation) became rather apparent, and wireless carriers began to literally run out of space on their networks in major markets.
The switch to digital protocols (TDMA, GSM, CDMA) that began in the early 1990's is now almost complete, and the U.S. Government will allow wireless carriers to terminate their AMPS service entirely on March 1, 2008.
AMPS has brought us some good times, if you think about it. Remember those 80's movies and TV shows that tried to look all high-techy with Sonny Crockett or Michael Knight making calls on a phone the size of a Korean War-era walkie talkie? You got it, that was AMPS. You can also make "You might be a redneck" type jokes about AMPS. For example, "If you're phone is the size of a toaster, you might be using AMPS." or "If you're cell phone tans one side of your face while using it, you might be using AMPS."
The latter joke here refers to the fact that handset transmitter output was, ahem, somewhat higher and less regulated back in the day. But don't worry, even if the phones did transmit enough microwave energy to cook poultry (note to attorneys: we're not saying they did), cell phone minutes were so expensive back then that hardly anyone could afford to talk on them for very long.
Keep an eye out for Alphabet Soup Part 2, The Revenge of TDMA
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Labels: cdma, cingular, evdo, gprs, gsm, pcs, sprint pcs, t-mobile, tdma, verizon
