I have a customer who's PRI runs fine for about 6-9 months at a time, but then reaches the point where is goes in and out daily. The phone system's error logs never report anything, but then Verizon swears that they don't see anything either. What is especially strange is that when Verizon comes out, they connect a test set, make a phone call and point it back at us as an equipment problem.
This has happened three times with this particular customer. Each time, we never have to do a thing with the hardware. After we convince the Verizon tech to make about five calls and answer another five, the circuit starts working fine. Again, aside from the usual swapping of cables, cards, etc., we never end up having to replace any hardware.
This circuit is on copper the whole way from the CO, which is only about a half-mile away from the site. The CO switch is a DMS-100.
The customer is starting to lose patience. Although they are in full agreement that this is a Verizon issue, since I can't provide them with definitive proof of what is causing it, I'm in the hot seat too. Can anybody think of what could be causing a PRI to stop working until a test set is connected and a few calls are made?
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Ed see if Verizon can install a commwatch at the site. Not sure if they have the ability, I know we use them but I is basically like a long term monitor.
We used to see circuits that techs would “clear†a trouble by simply reseating a card, a cable, or plugging in a test set. We used to call it shocking the circuit. The problem was that you knew the trouble would be back. Verizon doesn’t seem to like to replace cards unless a problem is proved. However, there are times that starting the eliminate items by replacing them is appropriate and I’d say this was one of them. Is there a 2nd PRI at the customer location so that the copper span could be swapped to see if the trouble followed the copper facility? Many of the cards have the ability to store data. I’d ask if the history shows anything. I’m not a DMS person but I’d say the same should be true of the switch and of any digital cross connect machine if there is one in the circuit. I suspect the DMS can look at both the ISDN information and the digital facility information. If the circuit is failing there should be data showing what type of failure took place. It may not point to an actual component. The problem is getting through to the right person at Verizon. Sounds like they need to have the problem looked at by techs in both transport and in switching.
You said the circuit runs fine for 6 to 9 months and it is on copper. What is the weather when it fails? We had a problem that we chased for weeks only to find that a gas tube was opening up due to summer heat. We were able to watch it fail with a meter.
I also had that same problem with Time Warner, they would point to us and we at them. We got tired of that so we replaced the PRI Card in the Switch. When it happened again, we said "Its not the hardware we replaced it" Time Warner had no choice but to do the same. They came back to the Customer and admitted that their switch was at Fault, my customer charged TM for my time and the Card replacement. Customer is Happy, problem resolved.
"The Only Stupid Question, Is the Question Thats not Asked."
Originally posted by bf6b5yr: We used to see circuits that techs would “clear†a trouble by simply reseating a card, a cable, or plugging in a test set. We used to call it shocking the circuit. The problem was that you knew the trouble would be back. Verizon doesn’t seem to like to replace cards unless a problem is proved. However, there are times that starting the eliminate items by replacing them is appropriate and I’d say this was one of them. Is there a 2nd PRI at the customer location so that the copper span could be swapped to see if the trouble followed the copper facility? Many of the cards have the ability to store data. I’d ask if the history shows anything. I’m not a DMS person but I’d say the same should be true of the switch and of any digital cross connect machine if there is one in the circuit. I suspect the DMS can look at both the ISDN information and the digital facility information. If the circuit is failing there should be data showing what type of failure took place. It may not point to an actual component. The problem is getting through to the right person at Verizon. Sounds like they need to have the problem looked at by techs in both transport and in switching.
You said the circuit runs fine for 6 to 9 months and it is on copper. What is the weather when it fails? We had a problem that we chased for weeks only to find that a gas tube was opening up due to summer heat. We were able to watch it fail with a meter.
* I’m thinkin’ along two of the same lines here for possibilities. Flakey card or port? HDSL card or DTC-I port off the DMS-100. - The HDSL card “should†have a PM log that can be looked at.
* Weather is also a thought I had… Every 6 to 9 months is when the problems come back up? Like when the weather turns warm? If there’s much aerial cable and the LMU (loop-make up) is at the edge of loss limits, hot summer sun shining on cable can increase resistance enough to make a difference and cause the circuit to start taking errors.
* My other thought on this one is an odd possibility but still possible…. Is the DS1 NID (smartjack) locally powered? Every once in a great while there’s a situation where a NID card will need to be locally powered off convenience power rather than span power. The down side of doing this is, sometimes cross-box connection (or any other splice points) can pick up corrosion.
Could it be moisture getting in a splice case and causing enough of a leak to deteriorate the service as well? Seen this happen a few times back in the day. Of course getting someone to spend the time to investigate the cable is another story as VZ probably does not have a PPM crew anymore.
Thanks for the feedback so far, guys. I'll try to answer a few questions here:
The copper is underground the entire route from the CO. I insisted that they cut the half-taps on this cable count dead to the field and they reluctantly did so at the pedestal at the street.
No, we don't have another span that can be used. We did for quite some time, but due to cost cutting measures, the customer eliminated their second PRI.
The HDSL card is definitely line-powered.
There isn't a cross box; these are true F1 pairs. There isn't a local splice case except for the internal splice chamber of the BET. I looked at the MS2 modules in there and they appear to be just fine. Same with the pedestal splice where the F1 cable is tapped.
As for the weather question, yes it does appear to happen in warmer seasons.
The Verizon tech commented on the fact that there is CO fiber at the premises and was wondering why they aren't using it for this customer's circuit. In a roundabout way, I think he was telling us that there is a known issue with this cable count without saying a word.
I seriously doubt that there are any repeaters on this circuit since it is only 2,000 feet from the CO. You can literally see the CO from the second story windows of this building.
Willing to share what I've learned in my past 40 years dealing with both ends of the phone line. Competent (Ihope) on Norstar, competent on Harris 20-20.
