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]]).

Ever wondered how the cellular companies find out when you are out of station and soar your mobile bill with roaming charges?

==SID Codescodes==

Well here's the culprit...

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.

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 you purchase thempurchased.The SIDA isphone used by mobiles to recognize when they are in their home system (e.g. it controls the "roam" light). Some newer phones maywill 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).

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]]).

==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). SIDs are programmed into the phone when you purchase them.The SID is used by mobiles to recognize when they are in their home system (e.g. it controls the "roam" light). Some newer phones may maintain a list of "preferred" systems identified by their SID code. The SID may also modify some signaling messages that are transmitted by 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.

The [[Preferred Roaming List|Preferred Roaming List ('''PRL''')]] is mostly responsible for determining which SIDs a phone could roam on.

With CDMA systems the [[Preferred Roaming List]] (PRL) is responsible for determining which areas a mobile can roam into. [[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 database]

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

[[Category:Mobile phone standards]]

[[Category:identifiersIdentifiers]]