[Asterisk-Dev] single bit T1 errors (Zhone again)

[Steven Critchfield]

Mainly for the archives here. I found this PDF to be very interesting in
explaining T1 signalling.

http://www.patton.com/support/pdf/t1-e1-pri_tech_over_lo-res.pdf

But note, that it appears to be a powerpoint presentation that has been
distilled to pdf form. It says confidential on the print out, but I
found it via google, search "q931 pri" second page, second entry.

On Tue, 2003-04-15 at 17:12, Jon Pounder wrote:
> Thanks Don,
> 
> You saved me a bit of math - I understand the basics of how the signalling 
> works, but as you, I am also unsure of whether the events in the driver 
> represent every bit that comes along, or just the changes in state of the bits.
> 
> I know there are a bunch of other people on the list with zhones, am I the 
> only one plagued with these issues, or has everyone else just tossed theirs 
> in the garbage or what ?
> 
> 
> At 04:50 PM 4/15/2003 -0500, you wrote:
> >On Tuesday, April 15, 2003 3:28 PM, Jon Pounder [SMTP:JonP at inline.net]
> >wrote:
> > > 1) does every signaling bit that comes along generate an event in the
> > > driver, or only the first bit of a given signaling type (ringing,
> > > hookstate, etc.) ? If so great, if not what handles this part ?
> >
> >I don't know if this is useful information as it is not driver specific
> >but is T1 specific. Framing and channel configuration have an effect on
> >signaling states. A signaling state is determined by looking at a
> >complete superframe, which will contain 2 or 4 signaling bits.
> >
> >If framing on a T1 is
> >ESF -
> >     4 signaling bits A, B, C and D (16 possible state) -
> >     superframe is 24 frames long. Signaling come from frames 6,12,18,24
> >SF -
> >     2 signaling bits A and B - (4 possible states)
> >     superframe is 12 frames long. Signaling bits come from frames 6 and
> >12.
> >
> >
> > > 2) do the events in 1) come in at a reliable interval as defined by
> >the
> > > media properties eg: T1 would have a certain fixed event rate per
> > > channel, and E1 would have another predictable but possibly different
> > > rate ?
> >
> >There would be a reliable interval for the state of a T1, one
> >superframe. One frame is 1/8000 of a second (125 micro second). So
> >every 1/8000 second there could be a new state.
> >
> >I have no idea how the driver passes on signaling. It could be bits or
> >states or change in states. Also, I do not know if there is any
> >performance monitoring that could be used to determine if bits are
> >being received in error.
> >
> >If any of this is useful great, if not sorry to have used the
> >bandwidth.
> >
> >Don Pobanz
> >_______________________________________________
> >Asterisk-Dev mailing list
> >Asterisk-Dev at lists.digium.com
> >http://lists.digium.com/mailman/listinfo/asterisk-dev
> 
> 
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-- 
Steven Critchfield  <critch at basesys.com>