Glossary

Glossary - E

ECSA

Exchange Carriers Standards Assoc.

EKTS

Electronic key telephone system.

Electronic Data Interchange

A network that allows access from any different locations for the transmitting of orders, invoices and payments electronically. The technology that is used is similar to e-mail but it has a much higher level of security. EDI operators posses computers that carry out the necessary centralised processing.

End Office (EO)

EO is an LEC (BOC or an ITC) switching system that exists within a LATA . Here local loops to customer stations are terminated for the purpose of interconnection with each other and also with trunks. CO (central office) and EO are commonly used interchangeably.

Entrance Facilities

First, in a premises distribution system, here lies the point of interconnection between the building wiring system and also the external telecommunications facilities (for example LEC networks, other buildings, and so on). Bellcore defines this interface with LEC networks as the end-user points of termination (POT). Second, it has a further specific meaning within interstate access, which is entrance facilities for interstate access (ENFIA).

EO

End office.

EPSCS

Enhanced private switched communications service.

ESF

Extended superframe.

ESN

Electronic switched network.

Ethernet

This is the most widely-installed LAN technology. It is standardised as IEEE 802.3. An Ethernet LAN uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol (which was originally developed so as to manage radio based data communications - hence therefore the name Ethernet). It runs over a coaxial cable or what is known as twisted pair wires. The most common Ethernet systems that are installed are called 10BASE-T and they provide transmission speeds of up to 10 Mbps. Fast Ethernet ( 100BASE-T10) provide transmission speeds of up to 100 Mbps and are typically used for LAN backbone systems or supporting workstations with 10BASE-T cards. A Gigabit Ethernet provides an even greater level of backbone support at 1 Gbps. One of the oldest LAN technologies that has been highly successful and is still popular. Originally developed by Xerox, Intel and DEC. It was first developed to run over coaxial cable however it can now run over twisted pair. Ethernet uses CSMA/CD and is closely related to the IEEE 802.3 standard by the fact that they share the same cable specification and also can communicate with each other. An Ethernet can run at up to 10Mbits/s.

ETO

The European Telecommunications Office. This is a staffed office that is located in Copenhagen and funded by ECTRA. It mainly carries out and co-ordinates studies in European telecommunications matters and does this on behalf of the EC and others.It also works in conjunction with ECTRA and ECTRA'S Project Teams.

Ex-directory

This is a directory status classification that leaves the customer's directory information unavailable from any of directory information services or their products.

Exchange Carrier (or local exchange carrier LEC)

An exchange carrier exists as a company (BOC or independent) that provides intra-LATA telecommunications, but only within its franchised area.

Exchange line

This is the telephone line that connects a customers' network terminating point to its local exchange.

Extended Superframe Format (ESF)

ESF exists as an extension of the superframe format of T1 carrier systems (12 to 24 frames) and also acts to perform the use of framing bits for error-checking and as a facilities data link (FDL)> Futhermore it completes frame synchronization. Please see superframe format.