GL-1
7510-A2-GB20-00
March 1997
Glossary
A single bit stream that combines two or more bit streams.
American Standard Code for Information Interchange. A 7-bit code that establishes
compatibility between data services. ASCII is the standard for data transmission over
telephone lines.
Devices that can be attached, either locally or remotely, to display or print the DSU’s alarm
messages.
A data transmission that is synchronized by a transmission start bit at the beginning of
a character (five to eight bits) and one or more stop bits at the end.
Attention Command Set. A group of commands, issued from an asynchronous DTE, that
allows control of the modem while in Command mode. All commands must begin with the
characters AT and end with a carriage return.
Asynchronous terminal interface. This feature allows a device to be controlled from an
async (asynchronous) terminal like an ASCII (VT100-compatible) terminal.
An operational mode in which the DSU forces automatic setting of the DDS line rate/speed
(56 or 64 kbps) as soon as a valid DDS network signal is detected.
The auxiliary communications port on a router.
Bipolar Violation. A modified bipolar signaling method in which a control code is inserted.
Circuit Card Assembly. A printed circuit board to which separate components are attached.
Consultative Committee on International Telegraphy and Telephony. See ITU.
Carrier Detect. A signal indicating that energy exists on the transmission circuit.
Associated with Pin 8 on an EIA-232 interface.
An independent data path.
Control Mode Idle. A control signal sent over the DDS line to indicate that no data is being
sent.
Communications port. A computer’s serial communications port used to transmit to and
receive data from a DCE. The DCE connects directly to this port.
Device software that sets specific operating parameters for the DSU.
Customer Premises Equipment. Terminating equipment supplied by either the customer or
some other supplier that is connected to the telecommunications network (e.g., DSUs,
terminals, phones, routers, modems).
Channel Service Unit. The function of the DSU that protects the T1 line from damage and
regenerates the T1 signal.
Clear to Send. An EIA-lead standard for V.24 circuit CT 106; an output signal
(DCE-to-DTE).
Data Communications Equipment. The equipment that provides the functions required to
establish, maintain, and end a connection. It also provides the signal conversion required
for communication between the DTE and the network.
Digital Data Service. Provides digital communication circuits.
aggregate
ASCII
ASCII Terminal or
Printer
asynchronous
AT Command Set
ATI
autobaud mode
AUX port
BPV
CCA
CCITT
CD
channel
CMI
COM port
configuration option
CPE
CSU
CTS
DCE
DDS
