From: Scott Morris (swm@emanon.com)
Date: Thu May 12 2005 - 16:25:54 GMT-3
Hehehe... Telco Voodoo Magic. :)
It's just a way to transport bits. The design concepts behind ADSL (shared
medium with varying xfer rates) are significantly different at the
telco-side of things than designing for HDSL or VDSL. So the assumptions
people have about DSL in general don't always apply.
For the telcos, it's all about conserving wire pairs. Physical
infrastructure is a pain in the butt to fix, upgrade and change out. So any
reuse is great!
Where can you learn more about it? Hmmmmm... Good question.
www.protocols.com perhaps, or Newton's Telecom Dictionary. It's just part
of my vast collection of useless knowledge from working in the field so
long!
HTH,
Scott
-----Original Message-----
From: Anthony Pace [mailto:anthonypace@fastmail.fm]
Sent: Thursday, May 12, 2005 3:11 PM
To: swm@emanon.com; 'Hogo, Trust'; 'Group Study'
Subject: RE: T1 delievered on 2 wires or 4???
Scott,
This is very good information. Where can I learn more about it?
ok. So people have come to believe T1=good DSL=flakey and opted for the old
tried and true 4 wires delieverd by the ILEC, with many repeaters along the
path; rather than gamble on DLS delievered by the CLECS. BUT now the
smartjack accepts the 4 wires comming from my router interface and converts
it to DSL so that it can be transmitted on 2 wires - and then does the same
conversion at the other end of the circuit (keeping the entire process
transparent to me)
Anthony Pace
On Wed, 11 May 2005 18:30:40 -0400, "Scott Morris" <swm@emanon.com>
said:
> A T-1 is 2-pair or 4 wires.
>
> However, many of the smartjacks are now HDSL capable (or VDSL
> depending on proximity to CO) and that is delivered over a single pair
> or two wires.
>
> The smartjack is doing magical conversion between the two. ;)
>
> HTH,
>
> Scott
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of Hogo, Trust
> Sent: Wednesday, May 11, 2005 6:05 PM
> To: Anthony Pace; Group Study
> Subject: RE: T1 delievered on 2 wires or 4???
>
> Hope this might help.
>
> http://www.cisco.com/warp/public/788/products/vwicmf_t1.html
> http://www.cisco.com/warp/public/63/wic-1dsu-t1.html
>
> ------
> HQ
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of Anthony Pace
> Sent: Wednesday, May 11, 2005 4:50 PM
> To: Group Study
> Subject: T1 delievered on 2 wires or 4???
>
> I recently terminated a T1 and ISDN PRI in a remote location and was
> able to see that the TELCO had terminated the T1 using a single pair
> and the PRI using a single pair from the 25 pair bundle coming into
> the Data Center's smart jacks.
>
> I was always under the impression that from the CSU/DSU (in my case it
> was built into the router) to the smartjack and subsequently the NI
> card in the MPO was 4 wires. 1 pair TX and 1 pair RX.
>
> Maybe between the CSU/DSU and the NI card it's 2 wires and then 4 for
> the distance to the CO? ??? I am confused because I always believed
> that DSL was born out of the efforts of finding a single pair
> alternative to
> T1 technology.
>
> Should PRI and DS1 be 1 pair or 2?
>
> Anthony Pace CCIE 10349
>
> --
> Anthony Pace
> anthonypace@fastmail.fm
>
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-- Anthony Pace anthonypace@fastmail.fm
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