X-Git-Url: http://git.jankratochvil.net/?p=gnokii.git;a=blobdiff_plain;f=Docs%2Fen_US%2Fgsm%2Fnetmon%2Ffaq_net1.htm;fp=Docs%2Fen_US%2Fgsm%2Fnetmon%2Ffaq_net1.htm;h=0a11599387193a46ae1ec0e57c4f637cbc24a7ac;hp=38423f42c31fcd2163983a1da95aedcbf7ad7956;hb=9243ae4a92a0e97f3c850018930fc50ff3f75544;hpb=1a6c5e5f47c4e40cacea0f72f0431e11a8dc9f0f diff --git a/Docs/en_US/gsm/netmon/faq_net1.htm b/Docs/en_US/gsm/netmon/faq_net1.htm index 38423f4..0a11599 100644 --- a/Docs/en_US/gsm/netmon/faq_net1.htm +++ b/Docs/en_US/gsm/netmon/faq_net1.htm @@ -1,503 +1,503 @@ - -
- - - - - - - -Here you can find explanation to some terms, which can be found in this FAQ: - -
ACCH (Analog Control Channel) -(TDMA 800/TDMA 1900) - -
AMPS (Advanced Mobile Phone Service)
-
Analogue cellular system working in 800 Mhz used, for example, in North America.
-
-
ASIC (Application Specific Integrated Circuit)
-
Electronic chips designed for some concrete purposes
- (for example, in phone it controlls communication between MCU and DSP)
-They're designed and produced by the companies which use them.
-
-
AVCH (Analog Voice Channel) -(TDMA 800/TDMA 1900) - -
BCC (Base-station Color Code)
-(GSM/DCS/PCS)
-
3-bit number (from 0-7 range) used to distinguish neighbor cells of the same operator,
-transmitting using BCCH in the same
-FDMA channel. Such distinguish is not needed when the cells belong to different operators
-(they use different channels and their BCCH are in different FDMA channels).
-It is given in BSIC of each BTS (you can check it for example in
-test 2).
-
-
BSC (Base Station Controller)
-(GSM/DCS/PCS)
-
It controls and supervises one or more BTSes.
-
-
BSIC (Base Station Identity Code
-or Base transceiver Station Identity Code)
-(GSM/DCS/PCS)
-
Unique ID number of each BTS. If we code this value binary, first three digits (in decimal format)
-are BCC and next three are NCC. These values range from 0 - 63.
-BSIC values can be found among others in test 2.
-
-
BTS (Base Transceiver Station)
-(GSM/DCS/PCS)
-
This device allows communication between phones and cellular network
-(many parameters, like current communication channel, distance to BTS and signal quality can be found, for example,
-in test 1).
-
-
And here are another classes with maximum power of BTS: - -
-
GSM 1800 | |
- -160 W (52 dBm) -80 W (49 dBm) -40 W (46 dBm) |
- -- -- -- |
- -10 W (40 dBm) -5 W (37 dBm) -2,5 W (34 dBm) |
In Polish version of this FAQ I give many links to WWW pages with BTS lists, their descriptions, pictures (in Poland). - -
From English pages I recommend www.geckobeach.com/cellular/cellpixs/cellid.htm -site - it's about networks and BTSes in North America. - -
Another links connected with it: - -
C1 (path loss-criterium)
-(GSM/DCS/PCS)
-
This is a parameter (ranging from -99 to 99 dBm) calculated by the phone to decide which cells to use
-(it uses the cell only if its C1 is positive). This value is based on:
-
-
-
It is calculated using following formula:
-
C2 (cell-reselection criterion)
-(GSM/DCS/PCS)
-
This parameter (-99 to 99 dBm) is calculated with following formula:
-
-
H(x) function for currently not used cells is 0 (if x<0) or 1 (if x>=0). For current cell H(x) is always equal 0.
-
By a skillful manipulation of this parameter (through CELL_RESELECT_HYSTERESIS), operators can direct
-connections to specific cells (thus lightening load of the network).
-
-
CDMA (Code Division Multiple Access; also known as IS-95)
-
One of the newer digital technologies in 800 or 1900 Mhz. Used in North America, Australia and some southeastern Asian countries
-(e.g. Hong Kong and South Korea). It doesn't divide the radio frequency
-spectrum into separate user channels by frequency slices or time slots, but
-separates users by assigning them digital codes within the same broad spectrum.
-
-
DCCH (Digital Control Channel) -(TDMA 800/TDMA 1900) - -
DCS (Digital Cellular System)
-
Cellular communication system working in 1800 MHz frequency band
-(currently more often called GSM 1800) a changed version of GSM (900 MHz) system.
-Its new features allowed to increase network capacity (thats why this system is used in urban areas with huge number
-of subscribers) at the cost of thick net of the base stations (BTSes)
-and to provide roaming within one country. GSM 1800 has different channel numbers
-(see test 17), different phone
-(see RX description) and BTSes
-transmission power and also different max speed of the user, at which he can use his phone
-(250 km/h in GSM and 130 km/h in DCS).
-
-
DSP (Digital Signal Processor)
-
Signal processor (digital signals processing chip - controls radio interface and speech coding/decoding).
-Its version can be checked in test 88.
-
-
DTCH (Digital Traffic Channel) -(TDMA 800/TDMA 1900) - -
DTX (Discontinous Transmission Exchange)
-
Some phones and networks "care" ;-) about battery life using so called discontinuous transmission (DTX),
-which turns off phones transmitter when we dont talk (but for example - listen to the calling party).
-During that period the phone generates a so called comfortable :-) noise, because if our interlocutor heard the silence,
-he could think that the connection was broken.
-
-
(GSM/DCS/PCS):
-
DTX must be supported by the phone (Nokia does - see
-test 78) and BTS - you can check and
-(sometimes) change this in test 12 and
-test 13.
-
-
FDMA (Frequency Division Multiple Access)
-(GSM/DCS/PCS)
-
This name means multiaccess on frequency field: transmission proceeds on different frequencies at the same time
-(this is a "full duplex" connection): there is a down-link from BTS to the phone and
-up-link - from the phone to BTS (this is called "up" and "down" because BTS
-antennas are usually higher than phone ones, so the signal from BTS to the phone
-really must go down (and vice versa)).
-
-
Frequency hopping (channel hopping)
-(GSM/DCS/PCS)
-
During connection your phone can continuously change used frequency (used channel) in communication with cell.
-It's used, when some channel is still troubled - without channel hopping
-communication with phone could not be possible, with it it's - only this
-part of transmition, which is made on this frequency, is lost (so, if gives less number of
-signal loss, but doesn't change sound quality - methods of coding it are always
-the same). You can check (during a call) if your phone uses this function in
-test 1. test 12 informs
-if it is allowed by the cell (these values are updated only during a call). Channel hopping requires
-Hopping Sequence Number (frenquencies are changed according to known for phone and network sequence)
-- see test 2.
-
-
GSM (Global System for Mobile Communication)
-
Cellular telecommunication system working at 900 MHz. It also has a 1800 MHz (DCS) and
-1900 MHz (PCS) version.
-
-
HLR (Home Location Register)
-(GSM/DCS/PCS)
-
Network register containing information about subscribers (i.e. about their subscribed services,
-tariff, last network they were logged in, etc.).
-
-
IMEI (International Mobile Equipment Identification code)
-(GSM/DCS/PCS)
-
Unique 15-digit identification number of every GSM phone on the world. It can be checked using *#06# code
-(all phones) or in service menu (Nokia), which can be activated by typing a code *#WAR0ANTY# or
-*#WARRANTY# (Nokia 6130). In Nokia 3110 after entering service menu (*#WAR0ANTY#)
-you have to additionally enter a code 9268. IMEI contains information about the manufacturer,
-place of production and serial number (check www.tele-servizi.com/janus/texts/imei.txt
-for such list for Motorola phones,
-here is my list for Nokia phones).
-Operators can restrict network access for particular phones for example the stolen ones
-(identified using IMEI number). Different operators can exchange such lists too.
-
-
IMSI (International Mobile Subscriber Identify)
-(GSM/DCS/PCS)
-
Unique (max 15-digit) number given to the phone:
-
-
-
- -IMSI attach
-(GSM/DCS/PCS)
-
It is a procedure executed after each power on. The phone informs network that it is active (and is ready for communication
-- receiving waiting SMS, etc.) and then it receives the IMSI number.
-The counter connected with IMSI attach is located in test 64,
-test 7 informs whether this is allowed by the current cell.
-
-
IMSI detach
-(GSM/DCS/PCS)
-
The phone informs network that it is going to switch off and the communication wont be possible
-(its IMSI expires). The counter connected with IMSI detach is located in
-test 64. test 7
-informs whether this is allowed by the current cell.
-
-
Location Update
-(GSM/DCS/PCS)
-
Every GSM phone periodically informs network about its current location.
-This function is called Location Update. It is executed after changing Location Area (phone makes
-it "intelligent" - when it's moved out of network coverage and the logs again to the network, makes Location Update
-only when current BTS has different LAC than previous one before losing the signal) or
-PLMN (after leaving the range of one network and trying to log in to another).
-Then information about Location Update is transferred to a new MSC/VLR,
-which in turn passes this information to HLR. When the phone works in new
-MSC/VLR, HLR doesnt identify the user by
-the number received from old MSC/VLR anymore. Location Update
-has a couple of varieties: PLU, IMSI attach and IMSI detach
-(they're distinquished in test 64). Current Location Area code can be checked in
-test 11.
-
-
MCU (Master Control Unit processor)
-
Main processor in phone.
-
-
MSC (Mobile Switching Center)
-(GSM/DCS/PCS)
-
Part of the system responsible for communication between subscribers and other users (also from other networks).
-
-
NCC (National Color Code or Network Color Code)
-(GSM/DCS/PCS)
-
3-bit number (from 0-7 range) used to differentiate cells of the operators from different countries
-(for example near the border, where the phone is in range of several different networks) transmitting using
-BCCH in the same FDMA channel. This number is constant
-within PLMN. It is given in BSIC of every BTS
-(you can check it in test 2).
-
-
PLMN (Public Land Mobile Network)
-(GSM/DCS/PCS)
-
Area covered by one operator (one network). After changing this area, the phone executes
-Location Update.
-
-
-
PLU (Periodic Location Update)
-(GSM/DCS/PCS)
-
The phone informs network, on which country area (in the range of which cells) it is located.
-This procedure is executed periodically (depending on the network, for example in polish
-Era GSM and
-Plus GSM networks every 3rd hour, in
-Idea every 2th hour)
-- this can be checked in test 10. This period is counted from the
-last contact with network (the counter doesnt stop even if the phone loses network signal!) from the last call, sending/receiving
-SMS, requesting some services (for example enabling call diverting), because the network is then informed about phones
-location (but this is not registered in test 64).
-The counter connected with PLU is in test 64.
-
-
TCH (Traffic Channels)
-(GSM/DCS/PCS)
-
Two way user data (computer data or digitized voice) channels. They can be divided to:
-
-
enabling | - -disabling | -
cell 0070 value for 78
- cell 011F value for 84 |
-
-cell 0070 value for 70
- cell 011F value for 7C |
-
When you network doesn't support one of these channel and phone recognizes its activation code, you may see -"Not ready" message. - -
You can check this in test 1. -The sequence of TCH channels can be freely set using some of the service programs -(for example WinTesla in Software/Product Profile menu) - it can be only possibility to enable HR channel in phone. - -
TDMA (Time Division Multiple Access)
-(GSM/DCS/PCS)
-
This means multiaccess in time: several phones can transmit signal (either digitized voice or computer data) in the
-same time on the same channel (its number can be checked in test 1)
-actually, this period of time is divided into very small parts (see TS description),
-invisible for us, so we can assume it happens simultaneously).
-
-
TMSI (Temporary Mobile Subscriber Identity):
-(GSM/DCS/PCS)
-
During signalization procedures encrypted on radio channel
-(for example, during location update) this number is assigned by
-MSC to phone. In the moment, when network wants to contact
-with concrete phone and transmission on radio channel is not encrypted, it's send
-instead of IMSI and allows phone to indentify, that concrete
-call concern on it. It doesn't have global meaning
-and it's structure is definited by network administrator. Actual TMSI
-you can check in test 10.
-
-
TS (Time Slot)
-
Each radio channel used in communication between phone and
-BTS is divided into 8 parts (called TS - time slots). If in all BTSes
-(available for your phone) all time slots are in use, you won't be able to make/receive a call and you'll get a 'Network busy'
-message (information about reason of connection failure is given among others in
-test 39). Unfortunately, each type of connection has the same priority in
-networks not supporting GSM Phase 2+ (it isn't available in older GSM Phases) - so if you want to dial emergency number 112
-and the network is busy, no other call will be interrupted and you won't get connected. This problem can also be solved by
-adding more BTSes (for example in dual GSM 900/1800 MHz network) or by modifying
-current stations to allow the use of HR channels (FR
-and EFR transmission uses whole assigned time slot, while HR
-(defined in GSM Phase 2) only half of it). Max data transmission speed using one TS is 9.6 kbit/sec (or 14.4 kbit/sec,
-but only in some additional conditions). There are new systems allowing higher transmission speeds
-(for example GPRS (Generic Packet Radio Services) or HSCSD
-(High Speed Circuit Switched Data), but they achieve this using several time slots
-at the same time (which decreases network capacity). Actual used TS can be checked
-in test 1, in phones with HSCSD (like Nokia 6210)
-use also test 8 for it...
-
-
VLR (Visitor Location Register)
-(GSM/DCS/PCS)
- Back to the top
This register contains the same data as HLR, but for roaming guests
-(their data are taken from their home network HLR).
-
-
-
-
-
Marcin Wiacek (WWW)
-
Last modification: 5 January 2002
-
-
-
+
+
Here you can find explanation to some terms, which can be found in this FAQ: + +
ACCH (Analog Control Channel) +(TDMA 800/TDMA 1900) + +
AMPS (Advanced Mobile Phone Service)
+
Analogue cellular system working in 800 Mhz used, for example, in North America.
+
+
ASIC (Application Specific Integrated Circuit)
+
Electronic chips designed for some concrete purposes
+ (for example, in phone it controlls communication between MCU and DSP)
+They're designed and produced by the companies which use them.
+
+
AVCH (Analog Voice Channel) +(TDMA 800/TDMA 1900) + +
BCC (Base-station Color Code)
+(GSM/DCS/PCS)
+
3-bit number (from 0-7 range) used to distinguish neighbor cells of the same operator,
+transmitting using BCCH in the same
+FDMA channel. Such distinguish is not needed when the cells belong to different operators
+(they use different channels and their BCCH are in different FDMA channels).
+It is given in BSIC of each BTS (you can check it for example in
+test 2).
+
+
BSC (Base Station Controller)
+(GSM/DCS/PCS)
+
It controls and supervises one or more BTSes.
+
+
BSIC (Base Station Identity Code
+or Base transceiver Station Identity Code)
+(GSM/DCS/PCS)
+
Unique ID number of each BTS. If we code this value binary, first three digits (in decimal format)
+are BCC and next three are NCC. These values range from 0 - 63.
+BSIC values can be found among others in test 2.
+
+
BTS (Base Transceiver Station)
+(GSM/DCS/PCS)
+
This device allows communication between phones and cellular network
+(many parameters, like current communication channel, distance to BTS and signal quality can be found, for example,
+in test 1).
+
+
And here are another classes with maximum power of BTS: + +
+
GSM 1800 | |
+ +160 W (52 dBm) +80 W (49 dBm) +40 W (46 dBm) |
+ +- +- +- |
+ +10 W (40 dBm) +5 W (37 dBm) +2,5 W (34 dBm) |
In Polish version of this FAQ I give many links to WWW pages with BTS lists, their descriptions, pictures (in Poland). + +
From English pages I recommend www.geckobeach.com/cellular/cellpixs/cellid.htm +site - it's about networks and BTSes in North America. + +
Another links connected with it: + +
C1 (path loss-criterium)
+(GSM/DCS/PCS)
+
This is a parameter (ranging from -99 to 99 dBm) calculated by the phone to decide which cells to use
+(it uses the cell only if its C1 is positive). This value is based on:
+
+
+
It is calculated using following formula:
+
C2 (cell-reselection criterion)
+(GSM/DCS/PCS)
+
This parameter (-99 to 99 dBm) is calculated with following formula:
+
+
H(x) function for currently not used cells is 0 (if x<0) or 1 (if x>=0). For current cell H(x) is always equal 0.
+
By a skillful manipulation of this parameter (through CELL_RESELECT_HYSTERESIS), operators can direct
+connections to specific cells (thus lightening load of the network).
+
+
CDMA (Code Division Multiple Access; also known as IS-95)
+
One of the newer digital technologies in 800 or 1900 Mhz. Used in North America, Australia and some southeastern Asian countries
+(e.g. Hong Kong and South Korea). It doesn't divide the radio frequency
+spectrum into separate user channels by frequency slices or time slots, but
+separates users by assigning them digital codes within the same broad spectrum.
+
+
DCCH (Digital Control Channel) +(TDMA 800/TDMA 1900) + +
DCS (Digital Cellular System)
+
Cellular communication system working in 1800 MHz frequency band
+(currently more often called GSM 1800) a changed version of GSM (900 MHz) system.
+Its new features allowed to increase network capacity (thats why this system is used in urban areas with huge number
+of subscribers) at the cost of thick net of the base stations (BTSes)
+and to provide roaming within one country. GSM 1800 has different channel numbers
+(see test 17), different phone
+(see RX description) and BTSes
+transmission power and also different max speed of the user, at which he can use his phone
+(250 km/h in GSM and 130 km/h in DCS).
+
+
DSP (Digital Signal Processor)
+
Signal processor (digital signals processing chip - controls radio interface and speech coding/decoding).
+Its version can be checked in test 88.
+
+
DTCH (Digital Traffic Channel) +(TDMA 800/TDMA 1900) + +
DTX (Discontinous Transmission Exchange)
+
Some phones and networks "care" ;-) about battery life using so called discontinuous transmission (DTX),
+which turns off phones transmitter when we dont talk (but for example - listen to the calling party).
+During that period the phone generates a so called comfortable :-) noise, because if our interlocutor heard the silence,
+he could think that the connection was broken.
+
+
(GSM/DCS/PCS):
+
DTX must be supported by the phone (Nokia does - see
+test 78) and BTS - you can check and
+(sometimes) change this in test 12 and
+test 13.
+
+
FDMA (Frequency Division Multiple Access)
+(GSM/DCS/PCS)
+
This name means multiaccess on frequency field: transmission proceeds on different frequencies at the same time
+(this is a "full duplex" connection): there is a down-link from BTS to the phone and
+up-link - from the phone to BTS (this is called "up" and "down" because BTS
+antennas are usually higher than phone ones, so the signal from BTS to the phone
+really must go down (and vice versa)).
+
+
Frequency hopping (channel hopping)
+(GSM/DCS/PCS)
+
During connection your phone can continuously change used frequency (used channel) in communication with cell.
+It's used, when some channel is still troubled - without channel hopping
+communication with phone could not be possible, with it it's - only this
+part of transmition, which is made on this frequency, is lost (so, if gives less number of
+signal loss, but doesn't change sound quality - methods of coding it are always
+the same). You can check (during a call) if your phone uses this function in
+test 1. test 12 informs
+if it is allowed by the cell (these values are updated only during a call). Channel hopping requires
+Hopping Sequence Number (frenquencies are changed according to known for phone and network sequence)
+- see test 2.
+
+
GSM (Global System for Mobile Communication)
+
Cellular telecommunication system working at 900 MHz. It also has a 1800 MHz (DCS) and
+1900 MHz (PCS) version.
+
+
HLR (Home Location Register)
+(GSM/DCS/PCS)
+
Network register containing information about subscribers (i.e. about their subscribed services,
+tariff, last network they were logged in, etc.).
+
+
IMEI (International Mobile Equipment Identification code)
+(GSM/DCS/PCS)
+
Unique 15-digit identification number of every GSM phone on the world. It can be checked using *#06# code
+(all phones) or in service menu (Nokia), which can be activated by typing a code *#WAR0ANTY# or
+*#WARRANTY# (Nokia 6130). In Nokia 3110 after entering service menu (*#WAR0ANTY#)
+you have to additionally enter a code 9268. IMEI contains information about the manufacturer,
+place of production and serial number (check www.tele-servizi.com/janus/texts/imei.txt
+for such list for Motorola phones,
+here is my list for Nokia phones).
+Operators can restrict network access for particular phones for example the stolen ones
+(identified using IMEI number). Different operators can exchange such lists too.
+
+
IMSI (International Mobile Subscriber Identify)
+(GSM/DCS/PCS)
+
Unique (max 15-digit) number given to the phone:
+
+
+
+ +IMSI attach
+(GSM/DCS/PCS)
+
It is a procedure executed after each power on. The phone informs network that it is active (and is ready for communication
+- receiving waiting SMS, etc.) and then it receives the IMSI number.
+The counter connected with IMSI attach is located in test 64,
+test 7 informs whether this is allowed by the current cell.
+
+
IMSI detach
+(GSM/DCS/PCS)
+
The phone informs network that it is going to switch off and the communication wont be possible
+(its IMSI expires). The counter connected with IMSI detach is located in
+test 64. test 7
+informs whether this is allowed by the current cell.
+
+
Location Update
+(GSM/DCS/PCS)
+
Every GSM phone periodically informs network about its current location.
+This function is called Location Update. It is executed after changing Location Area (phone makes
+it "intelligent" - when it's moved out of network coverage and the logs again to the network, makes Location Update
+only when current BTS has different LAC than previous one before losing the signal) or
+PLMN (after leaving the range of one network and trying to log in to another).
+Then information about Location Update is transferred to a new MSC/VLR,
+which in turn passes this information to HLR. When the phone works in new
+MSC/VLR, HLR doesnt identify the user by
+the number received from old MSC/VLR anymore. Location Update
+has a couple of varieties: PLU, IMSI attach and IMSI detach
+(they're distinquished in test 64). Current Location Area code can be checked in
+test 11.
+
+
MCU (Master Control Unit processor)
+
Main processor in phone.
+
+
MSC (Mobile Switching Center)
+(GSM/DCS/PCS)
+
Part of the system responsible for communication between subscribers and other users (also from other networks).
+
+
NCC (National Color Code or Network Color Code)
+(GSM/DCS/PCS)
+
3-bit number (from 0-7 range) used to differentiate cells of the operators from different countries
+(for example near the border, where the phone is in range of several different networks) transmitting using
+BCCH in the same FDMA channel. This number is constant
+within PLMN. It is given in BSIC of every BTS
+(you can check it in test 2).
+
+
PLMN (Public Land Mobile Network)
+(GSM/DCS/PCS)
+
Area covered by one operator (one network). After changing this area, the phone executes
+Location Update.
+
+
+
PLU (Periodic Location Update)
+(GSM/DCS/PCS)
+
The phone informs network, on which country area (in the range of which cells) it is located.
+This procedure is executed periodically (depending on the network, for example in polish
+Era GSM and
+Plus GSM networks every 3rd hour, in
+Idea every 2th hour)
+- this can be checked in test 10. This period is counted from the
+last contact with network (the counter doesnt stop even if the phone loses network signal!) from the last call, sending/receiving
+SMS, requesting some services (for example enabling call diverting), because the network is then informed about phones
+location (but this is not registered in test 64).
+The counter connected with PLU is in test 64.
+
+
TCH (Traffic Channels)
+(GSM/DCS/PCS)
+
Two way user data (computer data or digitized voice) channels. They can be divided to:
+
+
enabling | + +disabling | +
cell 0070 value for 78
+ cell 011F value for 84 |
+
+cell 0070 value for 70
+ cell 011F value for 7C |
+
When you network doesn't support one of these channel and phone recognizes its activation code, you may see +"Not ready" message. + +
You can check this in test 1. +The sequence of TCH channels can be freely set using some of the service programs +(for example WinTesla in Software/Product Profile menu) - it can be only possibility to enable HR channel in phone. + +
TDMA (Time Division Multiple Access)
+(GSM/DCS/PCS)
+
This means multiaccess in time: several phones can transmit signal (either digitized voice or computer data) in the
+same time on the same channel (its number can be checked in test 1)
+actually, this period of time is divided into very small parts (see TS description),
+invisible for us, so we can assume it happens simultaneously).
+
+
TMSI (Temporary Mobile Subscriber Identity):
+(GSM/DCS/PCS)
+
During signalization procedures encrypted on radio channel
+(for example, during location update) this number is assigned by
+MSC to phone. In the moment, when network wants to contact
+with concrete phone and transmission on radio channel is not encrypted, it's send
+instead of IMSI and allows phone to indentify, that concrete
+call concern on it. It doesn't have global meaning
+and it's structure is definited by network administrator. Actual TMSI
+you can check in test 10.
+
+
TS (Time Slot)
+
Each radio channel used in communication between phone and
+BTS is divided into 8 parts (called TS - time slots). If in all BTSes
+(available for your phone) all time slots are in use, you won't be able to make/receive a call and you'll get a 'Network busy'
+message (information about reason of connection failure is given among others in
+test 39). Unfortunately, each type of connection has the same priority in
+networks not supporting GSM Phase 2+ (it isn't available in older GSM Phases) - so if you want to dial emergency number 112
+and the network is busy, no other call will be interrupted and you won't get connected. This problem can also be solved by
+adding more BTSes (for example in dual GSM 900/1800 MHz network) or by modifying
+current stations to allow the use of HR channels (FR
+and EFR transmission uses whole assigned time slot, while HR
+(defined in GSM Phase 2) only half of it). Max data transmission speed using one TS is 9.6 kbit/sec (or 14.4 kbit/sec,
+but only in some additional conditions). There are new systems allowing higher transmission speeds
+(for example GPRS (Generic Packet Radio Services) or HSCSD
+(High Speed Circuit Switched Data), but they achieve this using several time slots
+at the same time (which decreases network capacity). Actual used TS can be checked
+in test 1, in phones with HSCSD (like Nokia 6210)
+use also test 8 for it...
+
+
VLR (Visitor Location Register)
+(GSM/DCS/PCS)
+ Back to the top
This register contains the same data as HLR, but for roaming guests
+(their data are taken from their home network HLR).
+
+
+
+
+
Marcin Wiacek (WWW)
+
Last modification: 5 January 2002
+
+
+