Phrack Inc. Volume 01 Issue 06 File 07

eZine lover (@eZine)

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Phrack Inc

 · 5 years ago

  

                                ==Phrack Inc.== 

                     Volume One, Issue Six, Phile 7 of 13 

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                              Cellular Telephones 
                      [Written By The High Evolutionary] 

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    I assume that most of us know many of the technical aspects of Cellular 
Phreaking therefore this file is intended for general information as to how 
these unique devices operate. 

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    Cellular is likely to be successful because it provides dramatic 
improvements over the historic automobile phones.  For years, mobile 
radio-telephone service was an extremely limited proposition.  There were only 
forty-four radio channels available, and a maximum of about thirty were 
assigned to any one area.  That meant if all thirty channels were occupied-one 
conversation per channel-and you were the thirty-first mobile phone user who 
wished to make a call, you would have to wait thirty minutes or more, even in a 
city the size of New York.  As you can imagine, mobile radio-telephone service 
like that could not become very popular.  Even with the limited number of 
channels, long delays in making calls during busy periods, and often poor 
quality transmission, there were big waiting lists for mobile service.  But 
with a fully equipped cellular radio-telephone system, it is possible to make 
5000 times as many calls simultaneously in the same metropolitan area, opening 
up the service to anyone that can pay the hefty prices. 

    That is because cellular radio-telephones systems are technically quite 
different from traditional mobile telephones.  First, the FCC (Federal 
Communications Commission) has allocated far more channels to cellular, 666 in 
all.  Second, those 666 channels are broadcast from many different locations. 
In the old mobile telephone systems, there was one powerful radio station with 
a large antenna that served an entire city.  In the new system, a geographical 
area is honeycombed with many cells, hence the name 'Cellular'.  Each cell has 
its own low-powered radio transmitter and receiver. As a car with a cellular 
telephone or a person carrying a portable moves from one cell to the next, the 
call is transferred automatically.  You're unlikely to notice when this 
transfer takes place, even though your phone is suddenly switched to a 
different radio station and to another channel while you are talking. 

    Because the cellular signal is low-powered, it doesn't go very far.  This 
permits the same channel you are talking on to be used for calls in other parts 
of the same metropolitan area without interference.  This would mean cellular 
radio-telephone systems can serve a very large number of customers in an area 
because there are more channels than before-and the larger number of channels 
are reused. 

    Unlike local telephone service, which is provided by a monopoly, there is 
competition in cellular.  Two classes of companies are allowed to offer 
cellular telephone service in every market.  One cellular system can be owned 
by a telephone company, the other by someone else.  The two-company rule was 
adopted by the FCC so that AT&T, which developed cellular, could not monopolize 
the whole thing. 

    Cellular Telephones come in two basic versions, as car phones and portable 
phones, with a briefcase hybrid.  Car phones are by far the most common, 
because they are much cheaper.  But most believe that, ultimately, portables 
will be the most popular.  Washington Post Company president Richard Simmons, 
whose company is a partner in several cellular systems, even predicts that by 
the early 1990's "There will be phones roughly the size of a calculators that 
you carry around in your pocket.  They will cost no more than five hundred 
dollars.  They will emancipate people from the necessity of locating a phone to 
make calls. The bad news is, you will never be able to get away from the phone, 
and we'll call it progress." 

    Car telephones include a small transmitter-receiver unit that is usually 
mounted in the trunk, an antenna and a control head that includes the handset. 
In most cellular systems, the telephone touchpad is located on the handset. 
Many domestic and foreign manufacturers make cellular car phones, but so far 
only Motorola makes portables, the DYNA T-A-C 8000X and 8000S. Motorola's 
portables look like a slightly enlarged, somewhat chunky telephone handset, 
with a stubby antenna at one end. 

    Portables are less powerful than car units, so they can't be used with some 
cellular systems.  The portable's other limitation is battery life.  A portable 
can listen for calls for about eight hours, but it can only transmit for only 
thirty minutes.  After that time it must be charged for a minimum of an hour. 

    The following American cities have cellular telephone service or soon will 
get it: 

                         New York         Denver 
                         Los Angeles      Seattle 
                         Chicago          Milwaukee 
                         Philadelphia     Tampa 
                         Detroit          Cincinnati 
                         Boston           Kansas City 
                         San Francisco    Buffalo 
                         Washington       Phoenix 
                         Dallas           San Jose 
                         Houston          Indianapolis 
                         St. Louis        New Orleans 
                         Miami            Portland 
                         Pittsburgh       Cleveland 
                         San Diego        Atlanta 
                         Baltimore        Minneapolis 
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