It Started With a Hardware Limitation I have been using Quectel GNSS modules in my designs for a while. They are reliable, well-documented, and the support ecosystem is solid. But the module I had been using had one problem that I kept running into: no external antenna support . For most projects that is a minor inconvenience. For a marine vessel monitoring and control system , it is a non-starter. A vessel hull blocks sky view, antenna placement is critical, and the difference between a clean fix and no fix at all often comes down to whether you can mount the antenna where it actually has line of sight. An integrated antenna in a sealed enclosure below deck simply does not cut it. So I went directly to Quectel. The Conversation With Quectel I reached out through their official sample request channel. I was not expecting much — most component manufacturers have a standard process: fill out a form, wait, get a few uni...
I have been working on some real time data acquisition and control application designing. Specially micro-controller based hardware designing and prototyping. For testing purposes i am using SIM900A GSM/GPRS module and FTDI UART converter. SIM900A module is connected to PC via FTDI converter. I use putty as a terminal program to communicate with the module. With required baud rates i am able to communicate with the module by sending a simple AT command (AT command set will vary with different modules) just sending AT the module replies with OK. This means module responded to the command sent from PC. Lets go ahead with TCP AT commands to establish a TCP connection to remote server via GPRS connection. I have run socket test software on remote PC and opened port 7777. You have to check your firewall or router settings to allow your preferred port. While the software start listening to port 7777, lets continue with the sending AT commands to module from the PC connec...