![background image](http://html1.mh-extra.com/html/nec/xen-master/xen-master_system-hardware-manual_4082722267.webp)
System Hardware Manual
A - 249
A
6
-32
400
0-64
2-0
1
–
R
e
le
as
e 4
.0
M
a
y
2
001
Glossary of
Abbreviations
Appendix A
The following table includes common abbreviations used throughout this
document that are listed in alphabetical order.
Abbreviations
Definition
ACD
Automatic Call Distribution
Provides a cost-effective method for supervising incoming telephone traffic
and associated staff activity.
ACR
Automatic Carrier Routing
Chooses the preferred trunk for an outgoing call based on the external
telephone number dialled.
BNC
Bayonet-Neill-Concelman
Connector for slim coaxial cables. This is similar to ones used with
Ethernet.
BRI
Basic Rate Interface
ISDN subscriber interface. BRI has two bearer B-channels at 64 Kbps per
second and a D-channel at 16 Kbps per second. The bearer B-channels are
provided for PCM voice, video conferencing, group 4 facsimile machines,
and other similar types of transmissions. The data D-channel used to bring
in information about incoming calls and take out information about outgoing
calls. BRI can also be used to access slow-speed data networks such as
videotex and packet switched networks.
There are two BRI standards:U Interface – 2-wire
T Interface – 4-wire
CRC
Cyclic Redundancy Check
CRC is a common method to establish that the data is correctly received in
data communications. This process checks the integrity of a block of data. A
CRC character is generated at the transmission end. Its value depends on
the hexadecimal value of the number of ones in the data block. The
transmitting device calculates the value and appends it to the data block.
The receiving end makes a similar calculation and compares its results with
the added character. If there is a difference, the recipient requests
retransmission.
DN
Directory Number
Unique number (phone number) assigned to each telephone or data
terminal.
DNIS
Dialled Number Identification Service
Allows the display of a name, extension number and caller ID for incoming
DID calls on subscribed ISDN lines.