It can either be mounted to a wall or laid flat on a table or bench top. If you are planning to utilize the flashing light feature, it will be most easily visible if it is wall-mounted. The unit should be within 15 feet of the telephone receiver to allow connection of the audio sensor. You will also need access to a 110V outlet to plug in the power transformer. The unit should be located at least 5 feet away from the nearest machine(s). If the machine is too close, the ambient sound from the ma