LMU-800 also can send messages via SMS and SMS alerts allows you to program will receive a predefined mobile phone with Scheduled Reports on any change event generated by the device. CalAmp LMU-800 offers the following interface for connecting external devices: 3 digital inputs, 3 digital open collector outputs, 1 analog input. To have more functions within the LMU-800 GPS tracker company CalAmp offers two accessories that are purchased separately, one is a relay to stop the vehicle engine in the field service management and other accessory is a conversion cable to install the device by contacting the vehicles OBDII port.