RS232 Serial to GPRS Gateway Software
The Gateway Python software allows the user to operate and control formerly RS232 serial only capable devices e.g. Data Loggers, Sensors, Programmable Logic Controllers (PLCs) remotely via the GSM (GPRS) network.
It supports 2 primary modes:
- Client Mode – The software acts as a client, remotely connecting to a server at a pre specified IP address and port. It can be either always connected, or connect only when data is received on the serial port.
- Server Mode – The software acts as a server, listening for connections from a remote client on a specified port (additionally a source IP can be specified, and only connections from this IP will be accepted).
In both modes any data received via serial will be forwarded over the GPRS network to the IP / port specified, and any data received from the server (via the GPRS network) will be forwarded to the serial port. The Gateway software is controlled via the use of SMS Command messages, these are standard text messages send via a mobile phone however they are formatted in a specific way that configure the Gateway software (i.e. change GPRS settings, serial port baud rate etc).
Two copies of the RS232 Serial to GPRS Gateway software and associated hardware may be combined to form a serial bridge:
RS232 Serial <---> Gateway Software <---> GPRS network <---> Gateway Software <---> RS232 Serial.
Alternatively a single copy of the RS232 Serial to GPRS Gateway software can be used with virtual COM port redirector software running on the PC (e.g. the HW Group VSP3 software - tested in software client mode, or Tactical Software Serial/IP® COM Port Redirector - tested working in both client/server modes) enabling the serial device to be located elsewhere and the existing desktop software not to require any modification. Information on Linux based COM port redirector software is availalbe from Wikipedia.
HW Group VSP3 Software: A customer has reported an issue with the "HW Group VSP3" software when sending the character 0xFF, therefore if your application uses this character you may like to instead consider using the open source GPL com2tcp application instead which reportedly works without any issues.
For the full SMS command list see the manual.