ISDN BRI S/T line-code violation

hi guys: When i read CCNP Remote Access study Guide,it's say that Logic zero bits are denoted by the presence of a +1 or -1 volt pulse. Logic one bits are denoted by the absence of a pulse. Each logic zero bit will alternate in polarity with respect to the previous pulse. A line-code violation is declared when two consecutive pulses remain at the same polarity.MY question is:in previous figure,on the s/t to nt1 direction,the DC Bits is -1 pulse,why the first B1 bits can be presence of -1 pulse,will not so cause line-code violation?

Reply to
asummit
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Right. This is called "Alternate Mark Inversion" or "AMI"

Right, decause it assume you must have missed one.

Uhhhh... What figure? Your question makes no sense.

Maybe

formatting link
will help you? The start of frame is marked with an AMI line code violation which ensures there is no DC signal and makes a clear start of frame.

Reply to
Phillip Remaker

Thanks for you reply,because the group can't display figure,so can i send the figure to you by email?

Reply to
asummit

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