Section 890.3725 - Powered environmental control system(a)Identification. A powered environmental control system is an AC- or battery-powered device intended for medical purposes that is used by a patient to operate an environmental control function. Examples of environmental control functions include the following: to control room temperature, to answer a doorbell or telephone, or to sound an alarm for assistance.(b)Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 890.9 .48 FR 53047, Nov. 23, 1983, as amended at 63 FR 59231, Nov. 3, 1998