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GLOSSARY
DCE
DDS
Dial-up
Digital
Digital Terminating
Equipment (DTE)
Digital Signal Level 0
(DS0)
Digital Signal Level 1
(DS1)
DTE
EIA
EIA/TIA-232-E
EPROM
Equalization
Equipment
Error Free Second
(EFS)
Errored Second (ES)
ESF Error Event
B-4
Data Communications Equipment. A term usually meant to refer to the modem
portion of a data communications network. Also, data circuit-terminating equip-
ment. In the case of an EIA/TIA-232-E (RS-232-C) connection, the modem is the
DCE; in a CCITT X.25 connection, the network access and packet-switching node
is the DCE.
Dataphone digital service; private-line digital service offered intra-LATA by
BOCs, inter-LATA by AT&T Communications, with data rates typically at 2.4,
4.8, 9.6, and 56 kbps; now a part of the services listed by AT&T under the Accunet
family of offerings.
The process of, or the equipment or facilities involved in, establishing a tempo-
rary connection via the switched telephone network.
Techniques and equipment in which information is encoded as either a binary
"1" or "0"; the representation of information in discrete binary form, discontinu-
ous in time, as opposed to the analog representation of information in variable,
but continuous waveforms.
Terminal equipment on the customer's premises. DTE includes the CSU func-
tionality which may or may not be physically incorporated into the same equip-
ment package as other DTE functions at the manufacturers' or customers' option.
DS0 designates a 64 kbps digital signal, a channel, comprised of 8,000 8-bit bytes
of customer data.
DS1 designates the combination of 24 DS0 channels plus overhead bits into a 1.544
Mbps T1 data stream. A DS1 signal is one that conforms to DS1 specifications.
Data Terminal Equipment.
Electronic Industries Association.
An EIA-specified physical interface, with associated electrical signaling, between
data circuit-terminating equipment (DCE) and data terminal equipment (DTE);
the most commonly employed interface between computers and modems.
Erasable programmable read-only memory.
The process of reducing the effect(s) of amplitude frequency and/or phase distor-
tion of a circuit by the introduction of networks to compensate for the difference in
attenuation and/or time delay at the various frequencies in the transmission
bands.
The customer-provided multiplexer (and its attachments) connected to the CSU.
An EFS is a second in which no error event has been detected.
An ES is a second with one or more ESF error events.
An Extended Superframe Format (ESF) error event is an ESF frame that contains
a CRC-6 error event or an OOF state, or both. ESF error events are processed to de-
rive ESs and severely ESs.
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