Category Archives: GSM

What Is GPRS and How GPRS Works? (GPS vs GPRS)

This article will discuss the technology behind GPRS to help give you a better understanding on how GPRS works.


GPS and GPRS are far different when it comes to functionality even though there’s only one letter that differ. As a technology, GPS stands for Global Positioning System which can track different sites on Earth as it receives data from satellites, while GPRS connects with the cell sites for signals to provide service for cellular phones.

So what does GPRS stands for?

What is GPRS?

GPRS stands for General Packet Radio Service. It is a non-voice wireless Internet technology that is very popular due to the fact that it can support both phone calls and Internet data transmission. Some GSM, or Global System for Mobile Communications, mobile phones can even handle both phone communication and Internet access at the same time. It transmits data packets on GSM systems where cell phone channels are shared.

How Does GPRS Work?

In GSM cell phone systems, there will always be idle radio capacity. This is the capacity of a network provider that is not being used and it stays unused until other cell phone users decide to make phone calls. GPRS uses this idle radio capacity to establish a data network to be used for data transmission. If a network provider’s idle radio capacity decreases, which means a lot of phone calls are being serviced, data transmission and speed decreases as well. Cell phone calls have a higher priority than Internet data transmission in cell phone network providers.


Due to its packet-based nature, which means it transmits data as a series of data packets routed through multiple paths across a GSM network, GPRS does not require a network to have continuous data transmission. This data transmission can share network radio channels easily and efficiently. These network radio channels have 8 time slots each and their maximum data transmission is 13.4 kbps. Every time slot that is not being used can be used by GPRS to transmit data packets. In a best case scenario, user can experience a GPRS data rate of approximately 170 kbps per network radio channel. In this scenario, only data transmissions are using the network channels without voice calls hogging the network.

Radio Channels

A GSM radio transceiver uses time division multiplexing to make 8 time slots possible for each radio channel. These channels are used by cell phone users for voice calls and data transmission in maximum effect if conditions are right like if there is no interference from nearby GSM cell towers, there are enough radio transceivers and there is a strong radio infrastructure. GPRS uses idle capacity in these radio channel time slots to accommodate data transmission.

How Does GPRS Work to Optimize Bandwidth?

When multiple channels are being used by voiced calls, GPRS combines these channels to make use of the unused capacity. This joining of multiple voice channels gives users higher bandwidth for data connections. The number of channels and the amount of capacity of a cell phone network remains the same but the bandwidth can now be allowed to reach its full potential by servicing both voice calls and data transmission all at the same time using the same channels.

GPRS technology is an elegant solution for network providers to offer additional services with minimal effort. Cell phone network providers only need to set up a few new infrastructure nodes plus some software upgrades while still using their existing GSM network infrastructure to add an overlay GPRS network to their cell phone service.


AT command set (SONY ERICSSON )

The GSM modem will respond in 2 ways, “ERROR” will be returned if the AT command is not supported.If the command is executed successfully an OK will be returned after the response text.e.g.

response text will be as follows;
+CBC :(0,2),(0-100)

List of AT Commands

  1. AT Attention command
  2. AT* List all supported AT commands
  3. ATZ Restore to user profile (ver. 2)
  4. AT&F Set to factory-defined configuration (ver. 2)
  5. ATI Identification information (ver. 3)
  6. AT&W Store user profile
  7. AT+CLAC List all available AT commands
  8. AT+CGMI Request manufacturer identification (ver. 1)
  9. AT+CGMM Request model identification
  10. AT+CGMR Request revision identification
  11. AT+CGSN Request product serial number identification
  12. AT+GCAP Request modem capabilities list
  13. AT+GMI Request manufacturer information
  14. AT+GMM Request model identification
  15. AT+GMR Request revision identification
  16. ATA Answer incoming call command (ver. 2)
  17. ATH Hook control (ver. 2)
  18. ATD Dial command (ver. 5)
  19. ATO Return to online data mode
  20. AT+CVHU Voice hangup control
  21. AT+CLCC List current calls
  22. AT*CPI Call progress information
  23. ATE Command echo (ver. 2)
  24. ATSO Automatic answer control
  25. ATS2 Escape sequence character
  26. ATS3 Command line termination character (ver. 3)
  27. ATS4 Response formatting character (ver. 3)
  28. ATS5 Command line editing character (ver. 3)
  29. ATS7 Completion connection timeout
  30. ATS10 Automatic disconnect delay control
  31. ATQ Result code suppression (ver. 2)
  32. ATV DCE response mode (ver. 2)
  33. ATX Call progress monitoring control
  34. AT&C Circuit 109 (DCD) control
  35. AT&D Circuit 108 (DTR) response
  36. AT+IFC Cable interface DTE-DCE local flow control
  37. AT+ICF Cable interface character format (ver. 2)
  38. AT+IPR Cable interface port rate
  39. AT+ILRR Cable interface local rate reporting
  40. AT+DS Data compression (ver. 3)
  41. AT+DR Data compression reporting
  42. AT+WS46 Mode selection
  43. AT+FCLASS Select mode
  44. AT*ECBP CHF button pushed (ver. 2)
  45. AT+CMUX Switch to 07.10 multiplexer (ver. 2)
  46. AT*EINA Ericsson system interface active
  47. AT*SEAM Add menu item
  48. AT*SESAF SEMC show and focus
  49. AT*SELERT SEMC create alert (information text)
  50. AT*SESTRI SEMC create string Input
  51. AT*SELIST SEMC create list
  52. AT*SETICK SEMC create ticker
  53. AT*SEDATE SEMC create date field
  54. AT*SEGAUGE SEMC create gauge (bar graph/progress feedback)
  55. AT*SEGUP SEMC update gauge (bar graph/ progress feedback)
  56. AT*SEONO SEMC create on/off input
  57. AT*SEYNQ SEMC create yes/no question
  58. AT*SEDEL SEMC GUI delete
  59. AT*SESLE SEMC soft key label (ver. 1)
  60. AT*SERSK SEMC remove soft key
  61. AT*SEUIS SEMC UI session establish/terminate
  62. AT*EIBA Ericsson Internal Bluetooth address
  63. AT+BINP Bluetooth input
  64. AT+BLDN Bluetooth last dialled number
  65. AT+BVRA Bluetooth voice recognition activation
  66. AT+NREC Noise reduction and echo cancelling
  67. AT+VGM Gain of microphone
  68. AT+VGS Gain of speaker
  69. AT+BRSF Bluetooth retrieve supported
  70. AT+GCLIP Graphical caller ID presentation
  71. AT+CSCS Select TE character set (ver. 3)
  72. AT+CHUP Hang up call
  73. AT+CRC Cellular result codes (ver. 2)
  74. AT+CR Service reporting control
  75. AT+CV120 V.120 rate adaption protocol
  76. AT+VTS DTMF and tone generation
  77. AT+CBST Select bearer service type (ver. 3)
  78. AT+CRLP Radio link protocol (ver. 2)
  79. AT+CEER Extended error report (ver. 2)
  80. AT+CHSD HSCSD device parameters (ver. 2)
  81. AT+CHSN HSCSD non-transparent call configuration (ver. 2)
  82. AT+CHSC HSCSD current call parameters (ver. 2)
  83. AT+CHSR HSCSD parameters report (ver. 2)
  84. AT+CHSU HSCSD automatic user-initiated upgrade
  85. AT+CNUM Subscriber number (ver. 2)
  86. AT+CREG Network registration (ver. 2)
  87. AT+COPS Operator selection (ver. 2)
  88. AT+CLIP Calling line identification (ver. 2)
  89. AT+CLIR Calling line identification restriction
  90. AT+CCFC Calling forwarding number and conditions (ver. 2)
  91. AT+CCWA Call waiting (ver. 2)
  92. AT+CHLD Call hold and multiparty (ver. 1)
  93. AT+CSSN Supplementary service notification (ver. 2)
  94. AT+CAOC Advice of charge
  95. AT+CACM Accumulated call meter (ver. 2)
  96. AT+CAMM Accumulated call meter maximum
  97. AT+CDIP Called line identification presentation
  98. AT+COLP Connected line identification presentation
  99. AT+CPOL Preferred operator list
  100. AT+COPN Read operator names
  101. AT*EDIF Divert function (ver. 2)
  102. AT*EIPS Identify presentation set
  103. AT+CUSD Unstructured supplementary service data (ver. 2)
  104. AT+CLCK Facility lock (ver. 5)
  105. AT+CPWD Change password (Ver. 3)
  106. AT+CFUN Set phone functionality (ver. 2)
  107. AT+CPAS Phone activity status (ver. 3)
  108. AT+CPIN PIN control (ver. 2)
  109. AT+CBC Battery charge (ver. 2)
  110. AT+CSQ Signal quality (ver.1)
  111. AT+CKPD Keypad control (ver. 7)
  112. AT+CIND Indicator control (ver. 5)
  113. AT+CMAR Master reset
  114. AT+CMER Mobile equipment event reporting
  115. AT*ECAM Ericsson call monitoring (ver. 2)
  116. AT+CLAN Language
  117. AT*EJAVA Ericsson Java application function
  118. AT+CSIL Silence Command
  119. AT*ESKL Key-lock mode
  120. AT*ESKS Key sound
  121. AT*EAPP Application function (ver. 5)
  122. AT+CMEC Mobile equipment control mode
  123. AT+CRSM Restricted SIM access
  124. AT*EKSE Ericsson keystroke send
  125. AT+CRSL Ringer sound level (ver. 2)
  126. AT+CLVL Loudspeaker volume level
  127. AT+CMUT Mute control
  128. AT*EMEM Ericsson memory management
  129. AT+CRMP Ring melody playback (ver. 2)
  130. AT*EKEY Keypad/joystick control (ver. 2)
  131. AT*ECDF Ericsson change dedicated file
  132. AT*STKC SIM application toolkit configuration
  133. AT*STKE SIM application toolkit envelope command send
  134. AT*STKR SIM application toolkit command response
  135. AT+CMEE Report mobile equipment error
  136. AT+CSMS Select message service (ver.2)
  137. AT+CPMS Preferred message storage (ver. 4)
  138. AT+CMGF Message format (ver. 1)
  139. AT+CSCA Service centre address (ver. 2)
  140. AT+CSAS Save settings
  141. AT+CRES Restore settings
  142. AT+CNMI New messages indication to TE (ver. 4)
  143. AT+CMGL List message (ver. 2)
  144. AT+CMGR Read message (ver. 2)
  145. AT+CMGS Send message (ver. 2)
  146. AT+CMSS Send from storage (ver. 2)
  147. AT+CMGW Write message to memory (ver. 2)
  148. AT+CMGD Delete message
  149. AT+CMGC Send command (ver. 1)
  150. AT+CMMS More messages to send
  151. AT+CGDCONT Define PDP context (ver. 1)
  152. AT+CGSMS Select service for MO SMS messages
  153. AT+CGATT Packet service attach or detach
  154. AT+CGACT PDP context activate or deactivate
  155. AT+CGDATA Enter data state
  156. AT+CGEREP Packet domain event reporting (ver. 1)
  157. AT+CGREG Packet domain network registration status
  158. AT+CGPADDR Show PDP address
  159. AT+CGDSCONT Define secondary PDP context
  160. AT+CGTFT Traffic flow template
  161. AT+CGEQREQ 3G quality of service profile (requested)
  162. AT+CGEQMIN 3G quality of service profile (minimum acceptable)
  163. AT+CGEQNEG 3G quality of service profile (negotiated)
  164. AT+CGCMOD PDP context modify
  165. Extension of ATD – Request GPRS service
  166. Extension of ATD – Request packet domain IP service
  167. AT+CPBS Phonebook storage (ver. 3)
  168. AT+CPBR Phonebook read (ver. 2)
  169. AT+CPBF Phonebook find (ver. 2)
  170. AT+CPBW Phonebook write (ver. 4)
  171. AT+CCLK Clock (ver. 4)
  172. AT+CALA Alarm (ver. 3)
  173. AT+CALD Alarm delete
  174. AT+CAPD Postpone or dismiss an alarm (ver. 2)
  175. AT*EDST Ericsson daylight saving time
  176. AT+CIMI Request international mobile subscriber identity
  177. AT*EPEE PIN event
  178. AT*EAPS Active profile set
  179. AT*EAPN Active profile rename
  180. AT*EBCA Battery and charging algorithm (ver. 4)
  181. AT*ELIB Ericsson list Bluetooth devices
  182. AT*EVAA Voice answer active (ver. 1)
  183. AT*EMWS Magic word set
  184. AT+CPROT Enter protocol mode
  185. AT*EWDT WAP download timeout
  186. AT*EWBA WAP bookmark add (ver. 2)
  187. AT*EWCT WAP connection timeout
  188. AT*EIAC Internet account, create
  189. AT*EIAD Internet account configuration, delete
  190. AT*EIAW Internet account configuration, write general parameters
  191. AT*EIAR Internet account configuration, read general parameters
  192. AT*EIAPSW Internet account configuration, write PS bearer parameters
  193. AT*EIAPSR Internet account configuration, read PS bearer parameters
  194. AT*EIAPSSW Internet account configuration, write secondary PDP context parameters
  195. AT*EIAPSSR Internet account configuration, read secondary PDP context parameters
  196. AT*EIACSW Internet account configuration, write CSD bearer parameters
  197. AT*EIACSR Internet account configuration, read CSD bearer parameters
  198. AT*EIABTW Internet account configuration, write Bluetooth bearer parameters
  199. AT*EIABTR Internet account configuration, read Bluetooth bearer parameters
  200. AT*EIAAUW Internet account configuration, write authentication parameters
  201. AT*EIAAUR Internet account configuration, read authentication parameters
  202. AT*EIALCPW Internet account configuration, write PPP parameters – LCP
  203. AT*EIALCPR Internet account configuration, read PPP parameters – LCP
  204. AT*EIAIPCPW Internet account configuration, write PPP parameters – IPCP
  205. AT*EIAIPCPR Internet account configuration, read PPP parameters – IPCP
  206. AT*EIADNSV6W Internet account configuration, write DNS parameters – IPv6CP
  207. AT*EIADNSV6R Internet account configuration, read DNS parameters – IPv6CP
  208. AT*EIARUTW Internet account configuration, write routing table parameters
  209. AT*EIARUTD Internet account configuration, delete routing table parameters
  210. AT*EIARUTR Internet account configuration, read routing table parameters
  211. AT*SEACC Accessory class report
  212. AT*SEACID Accessory identification
  213. AT*SEACID2 Accessory identification (Bluetooth)
  214. AT*SEAUDIO Accessory class report
  215. AT*SECHA Charging control
  216. AT*SELOG SE read log
  217. AT*SEPING SE ping command
  218. AT*SEAULS SE audio line status
  219. AT*SEFUNC SE functionality status (ver. 2)
  220. AT*SEFIN SE flash Information
  221. AT*SEFEXP Flash auto exposure setting from ME
  222. AT*SEMOD Camera mode indicator to the flash
  223. AT*SEREDI Red eye reduction indicator to the flash
  224. AT*SEFRY Ready indicator to the ME
  225. AT*SEAUP Sony Ericsson audio parameters
  226. AT*SEVOL Volume level
  227. AT*SEVOLIR Volume indication request
  228. AT*SEBIC Status bar icon
  229. AT*SEANT Antenna identification
  230. AT*SESP Speakermode on/off
  231. AT*SETBC Text to bitmap converter
  232. AT*SEAVRC Sony Ericsson audio video remote control
  233. AT*SEMMIR Sony Ericsson multimedia information request
  234. AT*SEAPP Sony Ericsson application
  235. AT*SEAPPIR Sony Ericsson application indication request
  236. AT*SEJCOMM Sony Ericsson Java comm
  237. AT*SEDUC Sony Ericsson disable USB charge
  238. AT*SEABS Sony Ericsson accessory battery status
  239. AT*SEAVRCIR Sony Ericsson audio video remote control indication request
  240. AT*SEGPSA Sony Ericsson global positioning system accessory
  241. AT*SEAUDIO Accessory class report
  242. AT*SEGPSA Sony Ericsson global positioning system accessory
  243. AT*SEAUDIO Accessory Class Report
  244. AT*SEGPSA Sony Ericsson global positioning system accessory
  245. AT*SETIR Sony Ericsson time information request
  246. AT*SEMCM Sony Ericsson memory card management
  247. AT*SEAUDIO Accessory Class Report

Nokia E51 WLAN Connection settings ( WiFi Settings)

Nokia E51 WLAN WiFi Connection settings
Following are steps to configure WLAN Connection settings

Main Menu ->  Tools -> Setting -> Connection -> Access Points -> Connection

Connection Name= anything you like (Hostel-003 in my case)
Data Bearer= Wireless LAN
WLAN network Name = you network name (Hostel-003  in my case)
Network status = Public
WLAN network mode = Infrastructure
WLAN security mode = open network
Homepage = none

Now, Select Option -> Advanse Settings

Proxy server address = server ip
Proxy port number = server port