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GPRS communiactions with .Net RRS feed

  • Question

  • I have been tasked with writing a C# / WPF app that displays location information of vehicle GPS tracking devices out in the field on a WPF Bing Map control. The devices use a GPRS modem for communications. The tracking device in question is a Meitrack device (http://www.meitrack.net/). This device can send and receive data via GPRS and SMS.

    Looking at the protocol, the device can transmit data to the server using this message structure:

        @@<Data identifier><Data length>,<IMEI>,<Command type>,<Command><* Check code>\r\n

    And the server can transmit data to the device using this structure:

        $$<Data identifier><Data length>,<IMEI>,<Command type>,<Command><* Check code>\r\n

    Now I'm unfortunately not very clued up with GRPS communications. My first question is, do I need a GPRS modem on the server side for all of this to work? Or can the tracking units transmit GPRS data to a specific IP address using TCP or UDP, where the server (with a static IP address) would be listening? If the latter is the case, it would be sufficient for the server to simply have an internet connection, and would not require a GPRS modem?

    However, looking at the protocol, I see a parameter called IMEI. This I know is a unique identifier for all cellular devices. So it looks as if that is the method of communications for this tracking device? I.e. All comms stays in the cellular network (and does not enter the internet) and communicates with other devices by addressing their IMEI? In this case the server WOULD require a GPRS modem.

    So my first question is if a GPRS modem will be required on the server side or not. Or can I get away with the server simply having an internet connection, and using IP addresses instead of IMEI or SIM numbers? And if that is the case

    > Blockquote

    , would each tracking device also require a static IP address if the server wished to talk back to the tracking device?

    Sorry for my ignorance. I've used GSM modems many years ago for sending and receiving SMSes via AT commands, but I've never used them for GPRS data.

    Thanks in advance for any support...


    Fabricio Rodriguez - Pretoria, South Africa

    Sunday, September 21, 2014 2:49 PM

Answers

  • If you search the source code of a Bing Map (from IE use menu View Source) you will find the latitude and longitude property in the map which is the GPS coordinates.  Bing need to make money and has made it difficult to scrape their webpages  from a VS application.  Yahoo maps had a dll that you could use, but the last time I try to use my code with the dll it also stopped working.  Hackers often bring down websites by flooding the sites with requests and not sure if the changes to Bing and Yahoo was to stop the hacker or to make more money.

    Usually the map webpage you use a HttpWebRequest, WebRequest, or a Browser.  HTTP (Browser) uses TCP for the transport layer and it is much more difficult to access webpages using a TCP application the using an HTTP class.


    jdweng

    Friday, September 26, 2014 6:02 PM