User`s guide

Glossary
GL-6
7800-A2-GB26-80
May 1999
Downstream health and status information has been truncated due overflowed system
limits with large amounts of health and status information in the subnetwork. Recover this
information by sending device health and status commands to specific modems.
Transmission in which the data characters and bits are transmitted at a fixed rate with
transmitter and receiver synchronized. This eliminates the need for start and stop bits as
used in asynchronous transmission, and is thus faster and more efficient.
A term for a digital carrier facility used to transmit a DS1 formatted digital signal at
1.544 Mbps. It is used primarily in North America.
Transmission Control Protocol. An Internet standard transport layer protocol defined in
STD 7, RFC 793. It is connection-oriented and stream-oriented.
Time Division Multiplexer. A device that enables the simultaneous transmission of multiple
independent data streams into a single high-speed data stream by simultaneously
sampling the independent data streams and combining these samples to form the
high-speed stream.
Advanced error correction coding technique for primary data typically used on higher
speed modems. This modulation scheme uses Forward Error Correction for multipoint and
high-speed point-to-point applications.
This indicates that the control DSU has not received a health and status update from the
tributary DSU within the specified time.
A unit that is under the control of another unit.
Unavailable Seconds. A count of one-second intervals when service is unavailable.
User Datagram Protocol. A TCP/IP protocol describing how messages reach application
programs within a destination computer.
An ITU-T standard for local and remote diagnostic loopback tests.
Virtual Circuit. A logical connection or packet-switching mechanism established between
two devices at the start of transmission.
Virtual Path Connection. In ATM, a unidirectional concatenation of Virtual Path Links
(VPLs) between Virtual Path Terminators (VPTs).
An outgoing signal transmitted when a DS1 terminal has determined that it has lost the
incoming signal.
Sub-tree Truncation
synchronous
transmission
T1
TCP
TDM
trellis-coded
modulation
tributary timeout
tributary unit
UAS
UDP
V.54
VC
VPC
Yellow Alarm