Cisco Systems 78-11450-03 specifications GL-4

Glossary

CO	Central office. The local telephone company office to which all local loops in a given area connect and
	in which circuit switching of subscriber lines occurs.
Command Line	See CLI.
Interface
Console	Data terminal equipment (DTE) through which commands are entered into a host.
Critical alarm	An alarm condition that might affect most or all subscribers that connect to the reporting node. To
	obtain more information about a problem, use the
	show facility-alarm status command. See also Major alarm and Minor alarm.

D

Data terminal equipment

DCE

DRAM

DS0

DS1

DS3

DSU

DTE

Dynamic random access memory

See DTE.

Data circuit-terminating equipment (ITU-T expansion). Devices and connections of a communications network that comprise the network end of the user-to-network interface. The DCE provides a physical connection to the network, forwards traffic, and provides a clocking signal used to synchronize data transmission between DCE and DTE devices. Modems and interface cards are examples of DCE. Compare with DTE.

Dynamic random access memory. RAM that stores information in capacitors that must be periodically refreshed. Delays can occur because DRAMs are inaccessible to the processor when refreshing their contents. However, DRAMs are less complex and have greater capacity than SRAMs. See also SRAM.

Digital signal level 0. Framing specification used in transmitting digital signals over a single channel at 64 kbps on a T1 facility. Compare with DS1 and DS3.

Digital signal level 1. Framing specification used in transmitting digital signals at 1.544 Mbps on a T1 facility (in the United States) or at 2.108 Mbps on an E1 facility (in Europe). Compare with DS0 and DS3.

Digital signal level 3. Framing specification used for transmitting digital signals at 44.736 Mbps on a T3 facility. Compare with DS0 and DS1.

Data Service Unit. Device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T1 or E1. The DSU is also responsible for such functions as signal timing. Often used with CSU, as in CSU/DSU.

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 devices such as computers, protocol translators, and multiplexers.

See DRAM.

	Cisco uBR10012 Universal Broadband Router Hardware Installation Guide
GL-4	78-11450-03 Rev.B0