Installation guide

Glossary
GL-13
Cisco 6260 Hardware Installation Guide
OL-2365-02
downstream
Data that is coming from the NI-2 card to the subscriber lines. See also upstream.
DS3
digital signal level 3. A framing specification used for transmitting digital signals at 44.736 Mbps on
a T3 facility. See also E3.
DSL
digital subscriber line. Public network technology that delivers high bandwidth over conventional
copper wiring at limited distances. There are several types of DSL: ADSL, IDSL, SDSL, and SHDSL,
to name a few. All are provisioned via modem pairs, with one modem located at a CO and the other
at the customer site. Because most DSL technologies do not use the whole bandwidth of the twisted
pair, there is room remaining for a voice channel. See also ADSL, IDSL, SDSL, and SHDSL.
DSL Forum
An organization of competing companies that sponsors an Internet Web site (http://www.adsl.com)
containing information about the applications, technology, systems, market, trials, and tariffs related
to DSL technology.
DSLAM
digital subscriber line access multiplexer. A device that connects many digital subscriber lines to a
network by multiplexing the DSL traffic onto one or more network trunk lines. The Cisco DSLAMs
include the Cisco 6015, Cisco 6100, Cisco 6130, Cisco 6160, and Cisco 6260. See also chassis and
multiplexer.
DTE
data terminal equipment. Device at the user end of a user-network interface that serves as a data
source, destination, or both. DTE connects to a data network through a DCE device (for example, a
modem) and typically uses clocking signals generated by the DCE. DTE includes such devices as
computers, protocol translators, and multiplexers. Compare with DCE.
Dynamic Host
Configuration
Protocol
See DHCP.
E
E1
Wide-area digital transmission scheme used predominantly in Europe that carries data at a rate of
2.048 Mbps. See also T1.
E3
Wide-area digital transmission scheme used predominantly in Europe that carries data at a rate of
34.368 Mbps. See also DS3 and T3.
EFCI
explicit forward congestion indication. In ATM, one of the congestion feedback modes allowed by
ABR service. EFCI is set by a network element to notify the destination end-system of congestion or
impending congestion in the network.
EIA
Electronic Industries Alliance. A standards organization made up of electronics industry
organizations. EIA is responsible for the RS-232C and RS-422 standards.
Electronic Industries
Alliance
See EIA.
electrostatic
discharge
See ESD.