VISIONTEK GSM Modem - 81GR is a wireless cellular connection for 2-way data communication with a wide variety of remote equipment and Utility applications. It is mostly used with energy meters and AMR applications. This modem provides a transperant GSM pipe for data transfer. Its specially designed power supply meets all the requirements of type tests and certifications as required by the utilities. Standard Power source is of AC 90-370 Volts with customized surge protection option