System identification number: Difference between revisions

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A '''Systemsystem Identificationidentification Numbernumber''' ('''SID''') is usedbroadcast by one or more [[base station]]s to identify a cellular network in a certain area (usually contiguous). It is aglobally Globalunique number to identifywithin [[BaseAdvanced station|baseMobile stations]]Phone for [[System|AMPS]], [[TimeDigital division multiple accessAMPS|TDMA]] or [[CDMA]] networks (the first two systems are essentially obsolete). This number sometimes has conflicts (see [[IFAST]]).

==SID Codescodes==

A '''System Identification Number''' ('''SID''') is used to identify a cellular network in a certain area. It is a Global number to identify [[Base station|base stations]] for [[AMPS]], [[Time division multiple access|TDMA]] or [[CDMA]] networks. This number sometimes has conflicts (see [[IFAST]]).

These codes are broadcast as 15 bit values but transmitted as 16 bits by core network protocols. They can be listed within a [[wireless device]] to show preference for one network over another. The additional bit in core network protocols allows the range of codes above 32,767 to be used for internal purposes, such as segregating billing records within a large area identified by a single broadcast SID.

[[Telecommunications Industry Association]] committee TR-45.2 assigned ranges to every country extant in the 1980s and national regulators assigned individual numbers. [[IFAST]] took over in 1997. This number space is 90% utilized for country ranges. Many countries do not use all of their allocated codes, hence the majority of codes are unused.

==SID Codes==

These codes are 15/16 bit values and can be listed within a [[Wireless Device]] to show preference for one network over another.

TIA TR-45.2 assigned ranges to every country in the [[1980]]'s and national regulators assigned individual numbers. [[IFAST]] took over in [[1997]].

This number space is 90% utilized, however many countries do not use all of their allocated codes.

SIDs are assigned by [[IFAST]] to every carrier (e.g., Verizon, Sprint, Alltel) by national regulators or [[IFAST]]. SIDs are programmed into the phone when youpurchased. purchaseA themphone will maintain a list of "preferred" systems identified by their SID code. The SID may also modify some signaling messages that are transmitted by mobiles (e.g. reducing the amount of information transmitted by "home" mobiles).

==How SIDs work==

When the phone is turned on, it listens for a signal. If it receives a signal, it looks at the SID (being carried by the signal), and compares it with the one that is stored in the phone. If they matchOriginally, thenin youanalog aresystems, inthe yourmobile homewould area.turn Youon arethe [[roaming]] indicator if youthe areSID inwas annot SIDthe areasingle thatvalue isstored notin recognized by yourthe phone.

TheWith CDMA systems the [[Preferred Roaming List|Preferred Roaming List]] ('''PRL''')]] is mostly responsible for determining which SIDsareas a phonemobile couldcan roam oninto. [[Base station]]s may also broadcast an [[List of mobile country codes|MCC]] and [[Mobile Network Code|MNC]] which can also be used by the PRL.

A typical SID area is about 30 - 60 miles in diameter, but some may be as large as 200 or more miles.

==External links==

*[http://www.mountainwireless.com/sid/ Mountain Wireless SID databsedatabase]

*[http://ifast.org/SID.htm IFAST SID Information]

*[http://www.rainyday.ca/~dialtone/ PRL Interpretations]

[[Category:Mobile phone standards]]

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[[Category:wireless communicationsIdentifiers]]

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