Digital access and cross-connect system (DACS): In communications systems, a digital system in which (a) access is performed by T-1 hardware architecture in private and public networks with centralized switching and (b) cross-connection is performed by D3/D4 framing for switching digital-signal-0 (DS-0) channels to other DS-0 channels.
Note: Modern digital access and cross-connect systems are not limited to the T-carrier system, and may accommodate high data rates such as those of SONET.
In the EIA/TIA 568-A standard, a horizontal cross-connect is used to describe the distribution station when such a station is separate from the main backbone, and accessed via horizontal cabling.
Source: from Federal Standard 1037C, Cisco Technical Glossary.