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GLOSSARY OF CELLULAR FONE TERMS
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ANALOG TRANSMISSION - A method of transmission in which information is encoded
     by continuously varying frequencies and amplitudes, such as sound waves
     and speech.                                                            

CARRIER - The telecommunications company that provides the customer with    
     telephone service.

CELL - A geographic subdivision of a metropolitan coverage area.

CELL SITE - A building housing the radio and control equipment necessary to
     interconnect a cellular "mobile unit" with the Mobile Telephone       
     Switching Office (MTSO).

CELL SPLITTING - The subdividing of existing cells into groups of smaller 
     cells to increase the call-handling capacity of the system.

CELLULAR - Geographic calling area divided into small cells; unique
     technology based on radio-telephony.

CGSA - Cellular Geographic Service Area, the area which a system operator is
     authorized by the FCC to cover.

CHANNEL - A radio frequency band assigned to a single transmitting radio.

DIGITAL - The coding and decoding of information into bits of data 
     representing 1's and 0's which in cellular allows for greater call quality
     and increased capacity.

DTMF - Dial Tone Multi-Frequency (touchtone).

DUAL-MODE - The ability of a cellular phone to use both the analog and digital
     voice channels in a cellular system.

ESN - Abbreviation for the Electronic Serial Number of a cellular phone 
     contained within a computer chip.

FREQUENCIES - The channel spaces on the radio spectrum used to accomodate
     data transmission.

HAND-OFF - The computerized transfer of a cellular telephone call from one cell
     site to the next as a vehicle travels between cells.

HANDS-FREE SPEAKERPHONE - An optional equipment device available on most new
     cellular phone models allowing the user to speak into a small microphone
     (usually clipped to the sun visor) while leaving the handset in its 
     cradle.

IMTS - Abbreviation for Improved Mobile Telephone Service, a service introduced
     in 1964.  Older conventional mobile phone service which uses only one
     transmitting tower for a city or area.

LANDLINE - The traditional telephone system used for stationary telephones such
     as conventional office and home phones.

LOCK - A cellular phone function that prevents unauthorized use.  The phone is
     unlocked by entering a 3- to 5-digit code.

MOBILE UNIT - The cellular telephone equipment installed in a vehicle.  It
     consists of a transceiver, control head, handset and antenna.

MTSO - Abbreviation for Mobile Telephone Switching Office.  The central office
     computerized equipment that coordinates and controls the routing and
     completion of calls in a cellular system.

NON-WIRELINE - Uses the "A"-band of cellular radio frequencies.  Type of 
     cellular carrier that does not also provide conventional phone-line 
     service to home or office telephones in the same local calling area.

PORTABLE UNIT - Cellular telephone that can be used outside a vehicle and
     operated from a miniature transceiver and battery poer.  Some models are
     hand-held units and others are transportable.

PROM/NAM - The computer chip located in the transceiver which contains the 
     mobile telephone number, the electronic serial number (ESN) and other
     system-related data.

ROAM ACCESS NUMBER - In order for someone to reach you while you are roaming,      
     they dial an access number for the roaming system you are in and your 
     cellular phone number.

ROAM INDICATOR - A signal on the cellular telephone that lights or indicates 
     the presence of a cellular transmission other than your home cellular 
     company.  To use the phone on an opposing system in a visited city, the 
     user will have to reset the "A/B" switch.

ROAMING - The ability to place cellular calls when traveling in other cities.  
     The cellular phone user is in effect "borrowing" anothr cellular system.

ROAMING AGREEMENT - The contractual agreement among cellular systems which
     allows the customjer to extend the use of his/her cellular phone in other
     cities.

TDMA - Time Division Multiple Access.  The digital technique that involves 
     dividing discreet amounts of time on a radio frequency into parts, then
     assigning different phone conversation to each part.

WIRELINE - Uses the "B"-band of cellular radio frequencies.  Type of cellular
     carrier whose parent company offers conventional home/office telephone
     service in the same local calling area.