sundance-communications.com/forum Forums General General Telephone & Systems Information Question about SLC96

Our office park is fed from Verizon using an AT&T SLC96. The use them a lot around here, though most newer pair gain installations are using equipment made by other manufacturers. I have been receiving conflicting information in these locations from Verizon. Their technicians refer to them interchangably as "RTs" or "pair gain" as well.

The issue is that DSL isn't available here, or so I have been told. We are clearly WAY too far from the CO for traditional copper (about 8 miles) so just about everything is using some form of pair gain equipment. This is where my question begins:

Isn't a SLC96 just a glorified channel bank? If so, I would think that it just takes in a T1 and emulates 24 analog circuits, correct? If this is true, it would explain their inability to pass the DSL signal. Have they come up with cards to retrofit the SLC96 to provide a remote DSLAM? It just seems that there is too much inconsistency since I know of locations in the same CO that are further out that can get DSL.

This is more of a curiosity question than anything since most customers here in our complex are going with T1/PRI or cable modem for their Internet access.

Ed,

SLC/pair gain are just channels. DSL is similar to the old AML --- you can only be so many feet from the C O. Now, IF (BIG IF) you are fed by fiber to the SLC, they can install the required cardage and your footage starts all over again (usually 17000 from the C O or SLC). But due to Judge Greene's ruling, the utilities won't normally do it because then the other utilities can by law use their facility at less cost. CATV and SBC both run in front of our business park --- neither will equip the SLC because the first one to do it will be the loser.

Isn't deregulation wonderful?

KLD

There are a couple ways to do that. You can upgrade your SLC96 with other manufacturer's components to put ADSL+POTS on a line card. What Qwest has been doing in residential areas is putting a remote DSLAM next to the cross box and dragging the customer lines through there to provide service. They will generally only do it on residential areas because of cost vs customer density. I have put a handful of the in business areas myself and it works well. We aren't using line sharing but the same principle applies.

It is basically like a channel bank but when running it as a gr303 setup you can providemany more lines per t1. An example is a slc fed by 7 t1's will support somewhere around 672 lines.
Basically the t1's act as available channels sort of like trunks.

Most of them I've seen have been running as TR-08, halfway between a normal channelized T1 and GR-303.

So, from the replies I have seen, the SLC96 is more of a remote switch, being that DS0 channels aren't really dedicated to a particular customer. They are more like trunks on a PRI, where the 1:1 ratio as with a T1 isn't the case. Channels are siezed and utilized on an as-needed basis. Correct?

sounds about right

* “...refer to them interchangeably as "RTs" or "pair gain" as well.”
- pair gain= generic term for digital carriers that are employed to serve customers rather than do inter-office. (There is/was an equipment manufacture that is called Pairgain which adds to the confusion.)
RT= remote terminal. The outside end as opposed to the Central Office End. That’s a completely generic term that would apply to all pair gain (using the generic term) devices.

* “Isn't a SLC96 just a glorified channel bank?” Yes, absolutely! Same mechanics as “D4” also… SLC96 operating in Mode I (II and III are more concentrated) is identical to D4 banks.

* “If so, I would think that it just takes in a T1 and emulates 24 analog circuits, correct?” Only in Mode I… again there are other configurations that allow more concentration of circuits than 24 to 1 bank.

DSL of any flavor will not pass through channel banks… Channel banks still operate on the philosophy of digitizing analog signals to place them on the digital carrier… There is no technology that could allow that sort of “fixed bandwidth” to ride a channelized T1 cxr.

DSLAM’s really require being fed by fiber… There are plenty of NGDLC (Next Generation Digital Loop Carriers) that, by definition, are broadband capable that can replace legacy DLC’s (remember DLC and pair gain with a lower case “p” can be used interchangably.) BUT unless that location is already fiber fed the swapping of systems is VERY time consuming and costly.

I can tell you're still a bit confused here...

SLC 96 is still a fixed ratio; it's just that one DS0 channel can be subdivided further to serve more than one dial tone service.

A SLC96 set up in Mode II and GR-303 acts very much just like a remote switch... BUT it has absolutey no intelligence in it... It's more or less just a pathway to the host switch.

That’s not entirely true the past couple of years… During Powell’s time at the FCC there was a ruling that NGDLC’s (again, broadband capable pair-gains) did not HAVE to adhere to CLEC pricing and availability.

Better rule in my opinion… BUT just another point to be confused on!