cabling G.SHDSL modems

[rfpup]

Hi to all!

We have a strange problem as below:
We use pairs of G.SHDSL back to back modems for extending ethernet cable through one copper pair to conncect remote ethernet equipments to one local ethernet switch.
There are about 60 G.SHDSL links which comes to PSTN and then come in our premises through one cable with 100 copper pairs 0.5 mm.
There are situation when three to four links goes down at the same time of the day or when their link quality decrease.
Is there any way how to avoid this situation?
Is there any ratio which we have to consider as % between used/unused pairs in the cable?
Thank You in advance

 

[buitenhek]

So...single pair high speed DSL over public network to ethernet both ends. Since DSL is shared, some company may be transmitting there daily log. What time(s) of day do these outages take place (6-10 AM, 11-1, 4-7 PM)?

Regards
Peter Buitenhek
ProfitDeveloper.com

"Never settle for a job well done...always look for cost cutting measures

 

[dagwoodsystems]

To answer your question directly: You do not need to maintain some standard pair distance for G.SHDSL-carrying copper. All flavors of SDSL--including HDSL and G.SHDSL--do not generate interference. However, such circuits can be affected by adjacent pairs carrying ADSL or 56K dialup modem carrier.

Clear something up for me. You first say that you're using these G.SHDSL modems in a back-to-back (shorthaul) fashion, which is fine. That's precisely the technology that Black Box, Patton Electronics and other manufacturers use for their "ethernet extender" devices.

You then say that "60 G.SHDSL links...comes to PSTN", which doesn't make sense. A true back-to-back connection isn't made over the public network, it's made over your own copper. Is this a university or other large campus type of environment? If so, that 100-pair cable you're talking about may be a local feeder, and not telephone company property. There's no mention of a DSLAM, which is why I'm pretty sure that this is all part of a hard-wired, private network.

Are you using one or two pair G.SHDSL? What's the approximate distance between the two modems? And please think about Peter's (buitenhek) question about the time of day. That information may prove to be important.

* * * *

Just a few months ago, I got a call from a property management company claiming that their first two voice lines were either busy or had horrible static. This was strictly a morning problem, because the lines would mysteriously "fix themselves" during the staff's lunch break.

Know what it was? Unsuitable riser-grade cable was used to extend the dialtone (from the demarc to a penetration point in the office) via the building's exterior stucco wall. The cable jacket was weather worn and crumbled to dust when touched. The exposed copped was then subjected to water from sprinkler heads every morning...hence the static or short. By afternoon, the sun had dried the wire.

The point of the story is that time and link quality may very well be related.

Tim Alberstein

http://www.dagwoodsystems.com

 

[rfpup]

Thank You buitenhek & dagwoodsystems for your replies!

To make my situation more clear the scenario is as below:

The remote sites use single copper pair of the PSTN to be connected, so the PSTN offeres only its copper pairs. The local site is connected to PSTN via a cable with 100 copper pairs. Each of the 60 pairs of this big cable (100 pairs) is connected to the PSTN with 60 links; each corresponding to one remote site. The G.SHDSL modems are not property of PSTN and this infrastructure is not mixed with any DSLAM of PSTN; The only thing that PSTN offers are copper pairs, nothing more.
It is used one pair G.SHDSL