Paradyne COMSPHERE
3610 User Manual page 98

COMSPHERE 3600 Series Data Service Units
DBU Dial Backup Unit. A device used for establishing a data channel on the public telephone network and for
switching data traffic there during a failure of the private line data channel.
D-channel The ISDN channel that carries signaling information to Control call setup.
DC Diagnostic Channel. The diagnostic interface between two network devices, used to extend the NMS
diagnostics to downstream devices.
DCE 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.
DCP Diagnostic Control Panel. See front panel.
DDD Direct Distance Dialing. Telephone exchange service, the public switched telephone network (PSTN) that
enables a telephone service user to access telephone lines without operator assistance.
DDS Digital Data Service, such as DATAPHONE Digital Service or ACCUNET Spectrum of Digital Services,
that provides digital (not dial) communication circuits.
dedicated backup A dial backup module (DBM) assigned to a particular DSU that is continually available for service
restoration. The DBM switches to Dial Backup mode automatically when the DDS line fails; no switching
is required. An external dial backup unit can also provide dedicated backup.
diagnostic path A method used by an NMS to extend diagnostic control to devices other than a tributary 3610 DSU at a
extension remote location. It uses one multiplexed channel to provide an external 1200 bps asynchronous
transparent path for the NMS's control channel.
dial backup module Ensures continuity of service if a DDS connection fails. Detects network failure, performs dial backup
functions, and automatically restores the DDS data path when the network returns to service. See DBM.
dial network See PSTN.
dial string A sequence of up to 36 characters that the DBM can send into the dial network to establish a call to a
remote backup device. It consists of a telephone number and may include other information, such as a
callback directory pointer.
digital bridging Provides the ability for dial backup of a multipoint configuration by bridging the signal on the digital side.
digital sharing Sharing device enabled allows TDM to backup MCMP use digital-sharing groups.
digital signal A signal composed of only two discrete values (representing the binary digits 0 and 1), used to transfer
data between a locally attached DTE and a device.
DIP switch Dual In-line Package switch.
DMI Data Mode Idle. Refers to a sequence of ones transmitted or received on the DDS or switched 56 kbps
network. Data Mode Idle operation is recommended for point-to-point applications.
downstream In extended networks, the direction in which diagnostic messages flow from the diagnostic control site to
any intermediate links and then to the final tributary modem.
DPII DATAPHONE II. The name of both a family of Paradyne NMS products (System Controller, Diagnostic
Console, and Network Controller), and the network management protocol used by these products.
DS0 Digital signal level 0 (zero). A 64 kbps digital telecommunications signal or channel.
DSD Digital sharing device.
Glossary-4 December 1996 3610-A2-GB46-60