Telos TWOx12 - Appendix 4 - Glossary of Useful ISDN and Telephone Terminology

TELOS TWOX12 USER’S MANUAL
GLOSSARY OF TELEPHONE TERMINOLOGY
APPENDIX 4 188
11.4 Appendix 4 - Glossary of useful ISDN and Telephone Terminology
You’ll get better results from the Telco if you understand, and speak, the lingo! We
have tried to include the typical acronyms used by telco personnel. We’ve put the
definition under the most commonly used acronym. For Intel’s ISDN glossary check
out: http://support.intel.com/support/isdn/ISDN_Glo.htm
Asynchronous Data
- A form of serial data communication which is not clocked. To
keep the bit stream synchronized start and stop bits are used which cuts down on
throughput. RS-232 computer data is commonly asynchronous data. In contrast to
synchronous data.
B Channel
- Bearer Channel. One of the multiple user channels on an ISDN circuit.
Used to carry user’s data; i.e. coded audio data in the case of Zephyr or ZephyrExpress.
Bearer Channel
- See B Channel
Behind the PBX
- This is our own definition and refers to when one privately owned
phone system is tied to another privately owned phone system. It is a limited Tandem
application. See Tandem Switch and Tandem Tie Trunk Switching below.
Bell Labs
. The basic research facility which was AT&T’s primary research facility.
Bell Labs was spun off with Lucent Technologies. Many very important discoveries
were made at Bell Labs including the transistor, communications theory, and radio
astronomy.
Bellcore
- BELL COmmunications REsearch. See Telcordia. The research and
development organization owned by the RBOCs. Bellcore represents the RBOCs in
developing standards for Telco equipment and in testing equipment compliance to
those standards. Bellcore also offers educational and training programs open to all
interested parties.
BERT
-Bit Error Rate Test- A test for digital lines which involves looping a data path
and sending a test pattern. Data returning is compared to the sent data to check for
errors. Depending on the “Test Pattern” used, BERTs may or may not uncover
problems. A line which only has occasional problems will need a BERT of sufficient
time duration to catch that intermittent solution. A five minute BERT will only catch
severe problems.
Bit Error Rate Test
-See BERT
Bit Rate
- The capacity of a digital channel. ISDN calls are set up at a given bit rate,
either 64Kbps or 56Kbps. The bit rate cannot be changed during a call. See Kbps.
Blocking
- When a circuit switched call cannot be completed. The percentage of
blocked calls to the number of calls attempted forms the basis of a statistic called
“grade of service”. While it is economically infeasible to build a network which would
have no blocking, the phone company are held accountable by the utility commissions
to keep blocking below tariffed levels. The concept of blocking cannot be applied to
packet networks, only circuit switched networks.
Both Way Trunks
- see combination trunks.