Order for the article "GPRS <-> COM (RS232)"?

Question

mobile connection

I want to read about communication with devices that have a COM port via GPRS.
1. Using a static and dynamic IP address for a SIM card.
2. Establishing a GPRS session with AT commands or a Java (c, c++) application (with command/code examples).
3. Used modems (pros and cons, price, availability in Russia).
4. Use of commercial developments
1) gprs-system.ru/index.php?option=com_content&task=v... they have other articles there as well.
2) www.radiofid.ru/ru/solutions/custody-transfer/heat... here is generally using a modem with openvpn on board.
Help with karma.
UPD. Added solution www.analytic.ru/products/8/info/based on Wavecom modem. I will read an article about the software implementation on this modem.

Answer 1

I join. Now I have a slightly different interest (QA [Sensors] -> rs485 -> [???] -> GPRS -> [Server] ), but I would read about the subject with pleasure.

Answer 2

1. Depends on the operator and APN, for example, static.beeline.ru is a static IP (if such a service is active), just internet.beeline.ru is dynamic.
2. first send "AT+CGDCONT=1,\"IP\",\"static.beeline.ru\"", and then "ATDT*99***1#", if both commands return OK - GPRS session is up .
3. a lot, the main disadvantage is that the 24x7 modem will not work, the session may “hang” by itself, the modem may “hang”. We need hardware additions to reboot the modem on command / call, etc. or by timer.
4. in addition to those indicated, I can promote the development of the company in which I work :) but here you need to understand what you want, because this option may be too redundant even in the minimal set.

Answer 3

Many people do this in metering devices.
look at ancom.ru - as far as I know, their modems are used for the data collection network from heat meters of MOEK, and in Russian Railways.
At one time, they offered to buy their development complete with a module. French module - I don't remember the name.