2 Replies Latest reply: Jul 31, 2012 7:05 PM by invisyguard RSS

How do I get a virtual rs232 port going


I have bout a gprs -dtu on ebay. 

New GPRS DTU RS232 RS485 to GPRS converter gprs modem ( 160786404223 )           


I though all I had to do was run a bit of software that was supplied and put in phone company name and sim card phone number.

Is there a system that does this?


I have bought a 3g data enabled sim card ( vodaphone) i had to but a usb wireless 3G modem to put the sim card into and connect to internet, then got to command prompt and type in C:>ipconfig /all  . Then write down the IP address of sim.


I can send TXT massages to unit and setup unit and get valid o.k responces, so the unit and sim work.


The chinese guy tring to help say I have to set up some kind of internet page for the unit to talk?


I did do some programming in assembler 10 years ago and sent AT commands to a GPS-GPRS unit through a PIC microcontoller, surely in this day and age it soulb be simple to set up a virtual com port.


I was wondering why I can not make an internet connection via the DIAL UP and just put the the sim card PHONE number.


I need to make about 50 of these units and the installers have no idea about computers ( there electricains who use UPstart UPB home automation software).  We can not use the end coustomers router or computer ( legal reasons ) so we want a total seperate link.


Thank you Dominic



  • Re: How do I get a virtual rs232 port going

    Hi Dominic,


    there are a couple of issues with your approach, but maybe this will help.


    Using a consumer SIM from a mobile operator won't usually give you a static IP address, so the IPconfig / all is only telling you a DHCP (temporary) address you have for that session.

    To setup a 3G connection, you don't usually need to enter the phone number anywhere - there are standard AT commands that you need to send (see a device development guide on this site as a good starter). You'll need to know the APN (access point name) that you want to connect to.


    You can usually get some expert advice and a service that is designed for your type of service from your local network operator. I know some people who have worked with Telstra in Australia and have been pretty successful, maybe it is worth you speaking to them.