The ISM4 can sync up to four IR controlled devices when referenced to one of those devices, typically a Video Monitor, Home Theater A/V Receiver or Whole House Audio/Video Entertainment System Controller. All four system devices are referenced to the ISM4 via Xantech Sensing Modules. There are 6 different sensors that can be used to detect voltage, contact closure, video, audio, light or current. When the System Reference Device is turned ON, the ISM4 will detect the change of state for the referenced device (from OFF to ON) and ‘look’ at the state of the other devices. If any or all are OFF, the ISM4 will automatically output IR Commands to turn those devices ON for proper system sync.

The ISM4 Processor constantly scans the Sense Inputs, whether any of the system devices are ON or not. This serves multiple purposes. First, when the System Reference Device is ON, it keeps the other system devices ON. That doesn’t just mean at the initial power up, but for as long as the reference device is ON. Some devices such as DVD players will time out after a certain period of inactivity. If a device were to time out or otherwise turn OFF, (as long as the System Reference Device is ON) when the ISM4 Processor scans the Sense Inputs, if any device is OFF the ISM4 will output the proper IR Command to turn the device ON and restore proper system sync.

The opposite is also true. If the System Reference Device is OFF and the ISM4 detects any of the other three devices are ON, the ISM4 will output the proper IR Command(s) and turn it/them OFF to restore proper system sync.