This Technical Report describes the physical layer connection device for local area networks. This device is sometimes referred to as the medium interface connector and is used between the terminal equipment and the trunk coupling unit for the trunk cable. The connectors described in this document were proposed by ISO/IEC JTC 1 SC 6, SC 13, SC 83, IEC TC 46, IEC TC 48, and IEC TC 86. This document focuses the work of all of these groups into one compendium which describes the physical devices which are currently available in the standards world. Data transmission techniques can be divided into two basic classifications: baseband and broadband. They can be further defined by the speeds of the data transmission across the interface. To avoid undue complexity, no attempt is made to describe the cable or wire used in conjunction with the connectors that are described.