ARC-10 is a top quality, easy to use GSM controller for alarming and remote control using SMS. The rail mount unit incorporates a Quad Band (850/900/1800/1900MHz) GSM/GPRS modem, two digital inputs, two power relay outputs and a serial RS-232 port. Up to five hundred users can be configured to switch a relay output with a toll-free phone call (e.g. for opening the garage door or a parking barrier). Ten users can be configured as alarm recipients.