Cabletron Systems HSIM-W87 manual Appendix C Wan Terms And Acronyms

APPENDIX C

WAN TERMS AND ACRONYMS

This appendix provides definitions for WAN terms and acronyms.

AIS — Alarm Indication Signal, The DS3 AIS is framed with “stuck stuffing”. This implies that it has a valid M-subframe alignment bits, M-frame alignment bits, and P bits. The information bits are set to a

1010... sequence, starting with a one (1) after each M-subframe alignment bit., M-frame alignment bit, X bit, P bit, and C bit. The C bits are all set to zero giving what is called “stuck stuffing”. The X bits are set to one. The DS3 AIS defect is declared after DS3 AIS is present in contiguous M-frames for a time equal to or greater than T, where

0.2ms<=T<=100 ms. The DS3 AIS defect is terminated after AIS is absent in contiguous M-frames for a time equal to or greater than T.

AMI — Alternate Mark Inversion, line coding used with both E-1 and T1. A digital 1 is encoded as a “mark” (pulse) and a 0 is encoded as a “space.” The marks alternate polarity.

ANSI — American National Standards Institute, the US member of the ISO.

Bearer (B) Channel — A 64 Kbps channel used with BRI and PRI ISDN services.

BPV — Bipolar Violation, the occurrence of two successive pulses of the same polarity in a bipolar signal.

B3ZS — Bipolar with 3 Zero Substitution, an AMI line code with the substitution of a unique code to replace occurrences of three consecutive zero signal elements.

B8ZS — Binary 8-Zero Substitution, line coding utilized with ESF (Expanded Super Frame) using a bipolar DS1 signal. Insures the ones density requirement for digital T-carrier facilities in the public network, while allowing 64 Kbps clear data per channel. This encoding method is not supported by some Telcos.

BER — Bit Error Ratio, errored bits over total bits, should be <10–7 for transmission lines.

HSIM-W87 User’s Guide C-1