Specifications

Glossary
23
Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
W
WAN (Wide Area
Network)
A network of transmission circuits generally spanning a large region or territory for transmission of
voice and data between widespread end users. An IGX/BPX network is an example of a WAN.
X
X.21
A CCITT standard for data interfaces transmitting at rates up to approximately 2 Mbps.
X.25
A commonly-used standard that defines the protocol for low-speed data packet networks.
XON/XOFF
A simple communications protocol for controlling the flow of data from one device to another. An
XON sent from a receiving device indicates it is ready to accept data and the transmitting device may
begin to output data. An XOFF from the receiving device indicates that it can no longer store any more
data and the transmitting device should temporarily cease transmitting.
Y
YY-cable(s)
A short adapter cable forming an electrical branch (thus the term Y) for connecting a single customer
data or trunk connection to two identical back cards to provide hardware redundancy on the IGX
switch.
Y-cable redundancy
A redundancy type used in the switch when a 1:1 card redundancy is implemented using a split or
Y-cable for the data connection between the user device and the primary and standby interface card.
Y1
A digital trunk conforming to the Japanese “Y” circuit standard, for use as a packet line. Similar to
T1, it operates at 1.544 Mbps.
yellow alarm
Another name for remote alarm as the remote alarm lamp on digital transmission equipment is always
yellow in color.