T1 service in Laval 1

[fs483]

Hello,

I'm thinking of adding a T1 service to my office. I want to know if it's possible to have a T1 service on the same physical line/number that already has an ADSL service (I don't think so but need to confirm). I currently have 2 physical lines/numbers and each one has an ADSL service. I want to avoid adding another physical line/number just to add the T1 service. One of my customer has an ADSL service on a line that doesn't have dialtone so I'm thinking that might be a way to go. I wonder if that can be done with a T1.

I've already contacted Telus, BellNexxia, AT&T, Sprint and AllStream and waiting for their sales reps to call me back. Are there any other providers in the Laval area ? What kind of questions should I ask and what kind of service garantees that I should expect with a T1 service ?

Thanks
anthony

 

[lopes1211]

T-1 uses 2 pairs of copper. It is a totally seperate interface from ADSL and regular phone lines. Apples and Oranges.

-CL

 

[ISDNman]

Lopes is correct. However to get a T1 you don't need to have POTS line just toget it the way you do with xDSL.

The copper pair(s) is includex in the price.

BTW, in many places they use HDSL or HDSL2 technology to transport the T1 to your premises. These technoogoies don't need repeaters every 5 k feet the way T carrier does. In fact HDSL2 only needs one pair to deliver a T1 out to 12,000 feet from the CO.

In any case, it is converted back to a 2 pair T1 at the smart jack, so this is all trasparent to the customer.

 

[SYQUEST]

HDSL doesn't have repeaters like T1, but it does have a similar device called a "doubler" or range extender, and these are usually placed the same distance as the T1 repeaters, beacuse the housings are already in place. HDSL does reduce provisioning costs, but it has its own set of problems compared to "repeatered" copper T1.

Fiber is better, if available.

I would never trust my T1 service to a single pair offering like HDSL2. All the single pair versions in Pacific Bell, I have seen, have been replaced with the 2-pair HDSL, even on short loops from a remote carrier terminal. Some of the companies that make HDSL hardware are: WESTELL, ADTRAN, PAIR GAIN™, and others.

Hope this helps!

....JIM....

 

[ISDNman]

The range extenders are not required and probably lower the reliability of the system if used for loops that are under (IIRC) 18 kft. Of course beyond 18 kft for HDSL and 12 kft for HDSL2 they are required.

Ameritech/SBC/AT&T here in Ohio seems to have HDSL-2 down. We've had numerous T1's from them or several CLECS where they provided the local loop and we've had virtually no problems.

About the only exception is that if an installer has the box open on the pole in a heavy rain it can cause the phantom power to get shorted out. The local Hi-cap guys said this is because the box is all corroded and filthy, but of course in this day of no maintenance whatsoever it never got cleaned or replaced.

Of course fiber is better, but fior a single T you are ot in the postion to demand anything so you gets what they gives.

On really nice thing about both the HDSL an HDSL2 is that the remote units have a number of very useful diagnositic LEDS that can give you a good idea if the circuit is nmarginal long before it goes down. Also, the serial port has lots of good info. I always check that *before* calling the Telco just in case they claim that everything looks ok and then clear the error stats. At least I know they are lying and I'll but a Netwok Probe on the line and then send the them the report after a couple of days to prove there are problems on the line.

YMMV

 

[SYQUEST]

The biggest problem with HDSL for T1 is that the T1 "envelope" is completely separate from the HDSL transmission. This means when the HDSL stops working or is intermittent you get NO T1 alarms at all!!! Your data and signalling can go to pieces, etc., but NO T1 alarms! The only way you will get a T1 alarm on HDSL is when one or both of the loops open or short and the HTU-R looses power. The problem with range extenders is they will go to "sleep"! I had this happen numerous times in San Diego, lots of long loops down there.

I even discussed this issue with one of the manufacturers, but it never went any where...

Also in Pacific Bell land, they have no automated way of interrogating the HDSL modules. In order to get the stats a craftperson in the CO plugs into the unit, just like you would from the field on the HTU-R end.

In one of our locations one of the other tenants had 8 T1s all HDSL. They had constant problems. We had 3 T1s and some intermittents at times. I finally talked to the outside plant engineer for the area and he sent thru an engineering request to place a fiber terminal in the building and put all the T1 service on fiber. That took about 8 months, but it got done and all the problems went away!

I had extensive experience with this stuff when I worked for a Paging Company. I was responsible for all the Telco stuff in California.

....JIM....

 

[fs483]

Thanks all. I started getting call backs from sales reps and they said that dial tone is not needed. Now I just need to find a provider with the right price.

akwong

 

[ISDNman]

My expereince has all been with Adtran HDSL2 stuff. These most definitely support red and yellow alarms.

Even better for most users is they have alarm lights right on the units. For example:

DSL LED :
--Off. NO sync on DSL
--Red poor quality on DSL link >1x10e7 BER
--Marginal signal quality (withing 2 dB of the above BER)
--Good Signal (greater than 2 dB margin)

DSX LED:
--Off: Network side DSX signal absent or is in wrong fomrat to match HDSL2 CO unit
--Blinking: BPV, frame bit error (SF only) or CRC erro (ESF only) detected at DSX (CO side) signal)

ALM LED:
Off: no alarm
Tellow: Remote alarm condition (e.g. yellow alarm)
Red: Detected local alarm condition locally or remotely

LBK:

That is a LOT of info without using any test equipment. IN addition if you have a key to the card frame the serial port has 15 minute stats for DSX (CO), H2TU-R to H2TU-C, H2TU-C to H2TU-R, and local DSX input stream.

Then again, if your telco can't make it work then you are better if they don't use it. If they are putting range extendes in every 7 kft they are reducing reliability of the system for now reasons.

Sounds like your problem was a bad cable. With only 3 T1's your must have been very convincing (read that "annoying") to have gotten them to put in fiber. Well done.

I'll grant you that not all the adtran cards have all these LEDS, though some do (this is right out the manual). Oh yeah, and Adtran has all their manuals online.

All the T1's here are using this Tech and it works fine here!

I guess a case of YMMV!

cheers

 

[SYQUEST]

ISDNman:

I guess you missed my point or I was not clear in my explanation. The problem is the T1 "level" does not reflect alarms or conditions at the HDSL "level" that affect or can affect the T1 transmission envelope of the HDSL.

So you may have "a lites on nobody home condition" but no or partial thru transmission on some channels or no signalling, etc. All the HDSL modules have LEDs on them, but not good if the true condition is not displayed or sent down stream.

In reference to extenders, no extenders were used on short loops, only long ones. Their are lots of long loops in the San Diego region... And some cable is not in the best shape in some areas.


....JIM....



In reference to the fiber terminal replacement above, there was a total of 12 T1s in the building serving the tenants, we had three of them.

 

[ISDNman]

Syquest,

Yes, I understood your point. Must not have been Adtran equipemnt though. Because we seem to have different results.

For example, if I disconnect one of my T1's from the CPE and put a tester on it (looking at just the rcv from Net stream) I see a yellow alarm.

The T1 CPE can see such an alarm and notify me. Once it does I can look at the LEDS (or use the serial port) to sectionalize the fault.

The ESF facilities data link passes through the system end to end (for some reason at least some systems allows this to be disabled) so that gives the Telco an error report from my CSU every 15 minutes.

I also know at turn up time if we are not ready it pisses off the Telco as they want to clear the Red alarms. This is true even if the service it self is not up, they want a CSU connected.

Of course if you are uisng SF then it may work differently.

If you run across this equipmetn in the future and need info let me know as I have a bunch of Pac Bell docs on it.

cheers

 

[fs483]

I finally got half the equipment for the T1 installed. It takes 5 appointments to have it installed. The first was to do a survey of the existing wiring. The second was to run inside cable. The third was to install the box with an interface card. What is this called ? I'm apparently forbidden to touch it except for the part were I plug a unit (probably the CSU/DSU or router or the loopback plug) which is supposed to be delivered on the fourth appointment. And finally on the fifth appointment someone is supposed to come and configure the unit ! No wonder why they charge a few hundred dollars for installation !

 

[Dexman]

That box on the wall is probably the Network Interface Unit or "NIU" for short. The telephone company is pretty strict about not wanting unauthorized people opening the cover and messing around inside.

 

[jeffmoss26]

it's also called a smartjack.

jeff moss

 

[fs483]

I always thought a smartjack was a little surface mount box. Didn't know it included circuitry other than shorting pins.

Thanks,

 

[Dexman]

A smart jack does include circuitry that allows the LEC or IXC (if applicable) to create a loop condition on the circuit for testing purposes.

Verizon (New England) uses them if a circuit is delivered to a customer's location using copper facilities.

Verizon will NOT use smart jacks if a circuit is delivered using fiber facilities. In those instances, Verizon will terminate to a simple RJ-48X, empty positions on an RJ-21X or a patch panel (depending on the end user's needs).

 

[SYQUEST]

In reference to Dexman, the reason that Verizon/Bell Atlantic does not install an NIU for a DS1 delivered via fiber is that the fiber MUX has one as a module in the MUX for the DS1. So nothing external is needed except the wiring and jack or termination ordered.

Most NIUs, T1 terminating repeaters, and HDSL HTU-R units installed since the late 1980s have had loopback capabilties.

....JIM....

 

[Dexman]

The problem with the ones internal to the fiber mux is that it cannot be looped back in the same way that you can loop back a 3113 or Adtran.

As a C.O. technician, when a T1 with a loopable NIU goes down, we use a T-Berd 224 and send an NIU loopback code to trigger a loopback condition in the smartjack if we cannot loop the CSU.

With a fiber mux, even if a circuit is good and an open condition is being caused by a faulty CSU, you can send the NIU loopback code till the cows come home and you will never get a loop. If the card in the mux can be looped remotely, Verizon has not made known the pattern, so we are forced to go the trouble ticket route if the CSU can't be reached.

 

[Dexman]

Of course, if it is during normal business hours, we request that the CPE be unplugged from the RJ-48X so we can check for a loop. If it is after hours, all bets are off.

 

[ISDNman]

Of course if the customer is using a CSU (remember those, at least on paper they are still required) the Telco can loop it back.

 

[Dexman]

True.

But in case of an after hours power failure, the lack of a smartjack means we have no way to tell if the cause of an All 1s condition is a legit T1 problem or a simple power failure.

If the user has all of their LDS service riding that circuit, we are forced to open a trouble ticket with Verizon or whomever.