My problem is that there is a legacy system for building automation (ventilation, temperature, lighting etc) without the possibility for upgrades, that needs to send text messages through a connected GSM modem. It does not have interfaces for connecting to the standardised SMS services around. The system is hosted in a virtual environment without the option for inserting physical equipment like GSM modems, even with a serial-to-IP converter.
What I'm trying to find is really some piece of software, commercial is fine, that can act as a bridge between the legacy system and the modern SMS services. The software would probably have to emulate the modem to receive and process the AT-commands from the legacy system, convert the data into a proper format, for example SMPP, and then forward the request to the SMS service for sending the message.
Another option is a simple software acting only as a virtual GSM modem, saving the messages somewhere (DB, files etc) for further consumption.
I'm stumped at the moment, so I hope some of you have seen some solutions for this somewhere.