# 2 GPRS modem need 2 static IP to send data?



## gyaku (Jan 21, 2009)

Hi Guys

I am designing a remote wireless GPRS modem housed in a small junction box in a remote island. The modem is controlled by a datalogger with AT commands. The modem sends the datalogger’s data through GPRS. 

The data will be sent to a receiver modem in my office hooked up to a PC software which controls the modem with AT commands. 

Correct me if I am wrong, the two modems each needs a sim card with static IP address, and they cannot use dynamic IP address because they cant find each other with changeable dynamic IP address. 

So here is my issue, wireless static IP address cost a lot, about $630 a month, two modems requires $1260 a month, compare that to wireless dynamic IP address which costs $20 a month! \(T0T)/ . Now I am selling the system to a customer, and I require to test with the two static IP address for only a few weeks, then I am stuck with a wireless contract for two years forking out $1260 a month!. 

So my question is, what I want to confirm is, normally for data GPRS transmission between two modems controlled with AT commands, I really do require TWO static IP address? 

No other way? I know that with GSM (not GPRS) the modems can dial each other with their phone numbers ( so no need for IP address). So is there some way the modems can communicate each other with phone numbers through GSM first, then transmit to each other the dynamic IP address with GSM, then switch to GPRS modem and communicate with each other with dynamic IP address? Just a thought.

Advance thanks. :1angel:


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## flyingsnow (Jun 23, 2009)

Hi, have you found a solution yet?

I am developing a very similar application but in a large scale. I have thousands of units (machine) out in the job sites and I need to communicate with them through whatever is available out there, including phone lines, GSM, GPRS, Internet, etc. to my PC/ Server in my office.

I prepare the data I need in packets and using Zmodem Protocol for transmitting data through phone line/ GSM and tested working successfully. Maybe you can give it a try.

Let me know if you have other solutions.


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## never.before (Jul 6, 2009)

hi 
i m trying to do something near that 
could u post steps 
and problem sharing to find solution


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