Among a variety of accessories shown by Systel, a radiocommunications engineering company based in Cairo, Egypt, was an alarm interface for TETRA radios. “We’ve got systems for vehicles, banks, warehouses”, explained Mohamed Mahmoud Sobhy, research and development engineer. “As you can see, we have this module connected to a TETRA radio device, and on the other side of the module we can have any kind of interface – for example, contacts, switches, analogue or digital switches. Whenever an alarm is triggered or a sensor is activated, it shows you on a plan where the intruder is. It can also show it on Google Earth, or on any map. Also it turns on the siren.”

The system can operate in reverse too, he adds. “You can send an SDS message to the radio that’s connected to the module, to turn on or turn off another circuit. For example, in a fire alarm or an emergency you can open doors automatically or close them.

“And we have almost the same thing, but for vehicles. You can monitor, control the car remotely, by using this module. We connect one side to the OED connector on the car, and the other side to the radio and then we actually monitor the car live. You can see the accelerometer as the car accelerates, and you can stop the car by sending an SDS message as well. You could stop it if someone steals it or if the glass is broken or a door is opened.”

All Systel’s developments are based on SDS messaging and so they can be expected to work on any TETRA network.