Spec Sheet Preview: The Alpha Communications® / S.T.R.™ 'NTR' series power supplies are used with a variety of S.T.R.™ (and other) intercom and video-intercom systems, to provide the low voltage power needed to operate the associated system components, and certain optional components and/or accessories. All of these power supplies now operate only on 220/240VAC primary power. All models are designed to easily surface mount right onto the finished wall by means of customer supplied screws or the convenient plastic 'Din Rail' bracket supplied with each power supply. All mode …