See also:
http://www.larscom.com/support/multimedia/acrobat/access-t/access-t.pdf
Watch the wrap. Pages 9 to 19
> -----Original Message-----
> From: Scott Brenner [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, December 21, 2000 9:46 AM
> To: Christopher Larson; 'Howard C. Berkowitz'; [EMAIL PROTECTED]
> Subject: RE: 56K vs 64K
>
>
> Here is a link to a White Paper on T-1 basics. It covers with moderate
> detail what you are wanting.
>
> http://www.ttc.com/downloads/white_papers/t1_tn.pdf
>
> There are many other White Papers on the page I found the
> this one on that
> might be of interest
> to everyone.
>
> http://www.ttc.com/technical_resources/white_papers/index.html
>
> -Scott Brenner
> CCNP/CCDP
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> Christopher Larson
> Sent: Thursday, December 21, 2000 5:47 AM
> To: 'Howard C. Berkowitz'; [EMAIL PROTECTED]
> Subject: RE: 56K vs 64K
>
>
>
> Could you post a link or somewhere to get this info. I have
> been looking
> and cannot find anything. I remember covering this in BCRAN and would
> like to go through it again. Having to do with the serial
> lines and the
> sampling rate, bit robbing etc. SF/ESF AMI/B8ZS etc. If you
> have a link
> to this info I would love to read it over again.
>
>
>
>
> -----Original Message-----
> From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, December 20, 2000 1:02 PM
> To: [EMAIL PROTECTED]
> Subject: Re: 56K vs 64K
>
>
> High-level view:
>
> Remember there are multiple levels in the "T1" world. I'm
> carefully avoiding "layer" If anyone starts trying to force this
> into OSI layering, I will start to mutter, "This is a .44 magnum, the
> most powerful handgun in the world. I can't remember if I've fired 5
> or 6 rounds. Feeling lucky, punk?" :-)
>
> The lowest level is the electrical/optical signal format
> Next, you have bit stream encoding (AMI, B8ZS, etc.)
> Next, you have framing (SF, ESF)
> And with voice services, you have call control (CCS, CAS, etc.)
>
>
> >
> >Bruce Williams
> >[EMAIL PROTECTED] wrote,
> >On a T1 line what is the difference between 56K and 64K. If I am
> correct I
> >believe that 56K uses bit stuffing to stuff the 8th bit of every
> timeslot
> >with a 1 to fulfill the ones density requirement. However, this would
> not be
> >necessary with B8ZS line coding, right because B8ZS will not allow 8
> >consecutive zeroes anyway.
>
> You're right about B8ZS, but 56K (and, for that matter, 48K) was
> introduced at a time when AMI was extremely common.
>
> >Now if that is true, why would you use 56K on a
> >B8ZS coded T1 circuit and if those timeslots are cross-connected to a
> 64K
> >line or vice versa, wont that cause errors because the two
> clock rates
> are
> >expecting different things in the 8th bit. I would appreciate any
> comments
> >at all on this subject.
>
> But the DS0 sees a 64 KBPS stream and doesn't inherently expect any
> meaning in any particular bit.
>
> Bit meaning does come up at a higher level when used for telco
> signaling, as with CAS and CCS.
>
>
> ------------
> I didn't even _think_ of the acronym CCIE while writing the body of
> this message. No ciscos were scaled, finned, or fried in its
> preparation.
>
>
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