An EAD socket was a network connection socket used in the early 1990s. They are now considered obsolete.

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

networking of this period (mid 1980s to mid 1990s) used "thin coax" or

10BASE2 10BASE2 (also known as cheapernet, thin Ethernet, thinnet, and thinwire) is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. During the mid to late 1980s this was the dominan ...

. All devices on a

network segment A network segment is a portion of a computer network. The nature and extent of a segment depends on the nature of the network and the device or devices used to interconnect end stations. Ethernet According to the defining IEEE 802.3 standards ...

connected to the same electrical section of

RG-58 RG-58/U is a type of coaxial cable often used for low-power signal and RF connections. The cable has a characteristic impedance of either 50 or 52 Ω. "RG" was originally a unit indicator for bulk RF cable in the U.S. military's Joint Elect ...

coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...

. Intermediate devices were connected via a T piece. The two ends of the segment were terminated with a resistive

network terminator In electronics, electrical termination is the practice of ending a transmission line with a device that matches the characteristic impedance of the line. Termination prevents signals from reflecting off the end of the transmission line. Reflect ...

. Although these networks were reliable when connected, they were prone to accidental misconnection by non-technical office staff. This was particularly an issue when devices, such as desktop computers, were being added or removed from the network. Although a rare need at this time, the situation was even worse for portable laptops. To avoid some of the drawbacks with 10BASE2 over

BNC connector The BNC connector (initialism of "Bayonet Neill–Concelman") is a miniature quick connect/disconnect radio frequency connector used for coaxial cable. It is designed to maintain the same characteristic impedance of the cable, with 50 ohm and ...

s, the EAD socket was one of several alternatives developed to give an "office friendly" network connector that could easily be connected and disconnected, and avoided the risk of making misconnections. With the obsolescence of 10BASE2 networks, from the mid 1990s, in favour of

Ethernet over twisted pair Ethernet over twisted-pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. They are a subset of all Ethernet physical layers. Early Ethernet used various grades of coaxial cable, but in 1984, Sta ...

, EAD sockets became obsolete. EAD is an abbreviation for German ''Ethernet-Anschlussdose'', and were developed from

TAE connector TAE (''Telekommunikations-Anschluss-Einheit'' or telecommunications connection unit) is the German standard for telephone plugs and sockets. The standard covers two TAE types: F ("Fernsprechgerät": for telephones) and N ("Nebenger� ...

s for telephony applications but were intended for connecting coaxial network cables like 10BASE2. A different mechanical encoding (Type ''E'') prevented mix-up with phone plugs. EAD cables were duplex connections replacing two thin-wire cables, with the T-connector integrated into the BNC end. The contacts of an EAD outlet are closed if no connector is plugged in. When a cable is plugged in, the normally-closed contacts in the socket are opened so that signals pass through the loop cable. Worn out connectors or outlets can cause the same problems that haunted the simpler connectors but user errors are largely reduced.

External links

Description of the EAD system at itwissen.info (in German)
RF connectors Ethernet cables {{network-stub