SMZ (TYPE *3) originally are designed for use in Type *3 Digital Distribution Frams (DDF) of BT (British Telecom), meet the requirement of BS ***0 F***2 (British Standard). Which are now widely used in telecommunication switching equipment. There are mainly three kinds, normal standard STD (space between *2.7mm), high density HDC (space between *0mm), ultra high density UHDC (space between 9mm). Which are also designed to support all types of network installations requiring high quality voice and video transmissions.