t1 in blue alarm but i can loop it

[paublo]

Hi not sure if any of you guys have ran into this, btu I have a VZ customer T1 that maps to my telco switch on a T3 card. On this particular T3 card I see that T1 port for my customer with a blue alarm.

Normally this would indicate that there is nothing plugged in on the customer side, however is there’s a cisco 1700. The weird thing is I can loop up the cisco 1700 and run to it with qrrs, 0’s etc. However the port status on my switch always shows a blue alarm.

I have tried several routers on the customer end and even replace the T3 card on my end, no matter what I do I still see a blue alarm even though I can run clean to the customers end which doest make sense.

We also had VZ go out there with a test set and I ran to that clean and his test set cleared the blue alarm when he was plugged into the smart jack.

Im at a loss on what’s going on here, how my t3 switch reports a blue alarm but I loop and run to it clean and I can run to VZ’s test set and see no alarm.

I have verified the t1 options on VZ and they are correct, ESF B8ZS etc.

 

[SYQUEST]

What kind of DS3 hardware are you using?

Is this a digital cross-connect or what?

Can you loop the NIU?

What happens if you connect another DS1 device to the DS1?

Does it still show a blue alarm?


....JIM....

 

[paublo]

Jim,
I'm using a Lucent Cascade Switch that VZ maps my customer T1s to. The switch terminates several T3's that the t1's are mapped to.

I can look the NI without any issues with multiple patterns.
I tried several DS1 devices and the blue alarm is always present.

this is a strange one, i know.

 

[kwing112000]

Sounds like there is a crossover in place or a staight cable when there needs to be a cross. i have seen Verizon T1s come in wired backwards. maybe worth a shot.

Kevin Wing
ACA- Implement IP Office
Carousel Industries

 

[ronromano]

Yellow is customer, red is carrier, blue is out of frame. You could still loop a t1 in blue. Tell Verizon, out of frame and you want a vendor meet on it. It will be fixed before you get there.

http://www.nu-tel.com

 

[paublo]

im looping unframed to the NI as the customer CPE provides the framing.

 

[jerryreeve]

http://www.gl.com/monitort1e1.html

Blue Alarm (T1 Only):

This will flash when a blue alarm is detected. A blue alarm is defined as the reception of unframed all ones condition. The algorithm used is to simultaneously check for an out-of-frame (OOF) condition, and check for 14 or less zeros out of 13,895 bits. All bits, including framing bits, are tested. The alarm is cleared if OOF condition clears, or if 15 or more zeros are counted within 13,895 bits.

A blue generaly means that the upstream device is either looped or off line.

the cisco might be stuck in a loop condition or there might be a hard loop on the system that you are thinking is coming from the cisco.

----------------------------
'Rule 29', "The enemy of my enemy is my enemy's enemy. No more. No less."
----------------------------
JerryReeve
Communication Systems Int'l
com-sys.com

 

[paublo]

i have used to cisco routers and i know they are in working condition but the blue alarm remains when either of the two routers are plugged in to the jack. these cisco's work on another jack at the customer location without any issues.

also as noted the VZ tech's test eq clears the alarm.
If they was a telco loop i wouldn't see a blue alarm.

 

[SYQUEST]

Just to review a few items, you said VZN tested from the NIU and found no fault.
**Did VZN use the modular jack on the NIU or the BANTAM test jacks for DS1 access?
**Where did they access the DS1 in the other direction for testing?
**When you connected the Cisco 1700, were you plugged into the modular jack on the NIU or a different jack wired to the NIU?
**Have you tried putting a loop plug at the jack on the NIU?
**What happens if you put a loop toward the NIU from the CBX500 and test at the NIU like VZN?

My impression of the problem seems to be you have a physical problem, and in order to solve it, you need to sectionalize the circuit in order to find the errant portion. Answering the above questions may provide a solution or more clues. Keep us updated.

....JIM....

 

[paublo]

Jim,


VZ used the Jack on the Ni to test and throw a loop towards me switch, which i could see run to it and it cleared the blue alarm.

VZ accessed the jack at the customer's location.

My customer had the routers directly plugged into the NI and did not have it extended.

I did try to put a loop on the NI and it does clear the alarm and i can run to it but then again i can run to the cisco's even though its in blue alarm.

thanks for the reply Jim.
This one is weird and i think we may just try to order another line instead of fighting VZ as we have no proof its them at this point.

 

[SYQUEST]

With the Cisco router connected to the DS1, have you put a DS1 test set on the monitor jacks of the NIU to see if the BLUE alarm shows at that point?

What kind of NIU is installed?

Is the local loop an HDSL design? One pair or two?

Does the Cisco show any alarms?

....JIM....

 

[paublo]

Its and RJ48C, in position 6 of 8.
The cisco does show an alarm light on the wic, I believe, but again i can loop it and the alarm goes away when i run a loop.

As far as the HDSL design, i believe it might be HDSL2.

 

[jerryreeve]

Get an O'scope out and look at your test points, you should be able to quickly determine where the "all ones" condition is coming from.

----------------------------
'Rule 29', "The enemy of my enemy is my enemy's enemy. No more. No less."
----------------------------
JerryReeve
Communication Systems Int'l
com-sys.com

 

[allisland]

You may want to check out the following Cisco site for your Blue Alarm!

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00800a7100.shtml