One of a hierarchy of North American data transmission rates associated with ISDN and B-ISDN, 44.736 Mbps. The terrestrial and satellite format for transmitting information digitally. DS3 has a capacity of 672 voice circuits at a transmission speed of 44.736 Mbps (commonly referred to as 45 Mbps). DS3 is used for digital television distribution using mezzanine level compression – typically MPEG-2 in nature, decompressed at the local station to full bandwidth signals (such as HDTV) and then re-compressed to the ATSC’s 19.39 Mbps transmission standard.