sundance-communications.com/forum Forums TDM Business Telephone Systems Avaya - Lucent Telephones & Systems Definity s8500 analog ring cadence

Dave are these modems some sort of card or device or are they just going straight into some sort of computer?

The reason I ask is that liquidvw and myself do work on the S series servers and have not had this type problem. I have 6000 stations behind my servers and have not seen anything like you are describing.

I also looked at the Avaya technical site for known issues with different servers and releases of software, and didn't find anything for you that would point this problem back to the S8500, or the release of software.

The only issues I have seen is analog lines into a Brook trout card and the modem would not pick up calls. I finally pointed this vendor to upgrade their firmware for the Brook Trout card as their were know issues.

Here is a screen shot of what liquidvw is talking about of you want your customer to try it Dave.

I've forwarded this information up the food chain along with a change order request, but doubt that changing the codec will change the ring cadence.

I didn't say that making the change required travel, just that the testing part of it requires travel. I'm not at liberty to get into any further details as to "why" that is.

Thanks,

They are industrial, rack mounted modem shelves that address some specific needs of this particular project.

The "computers" in this case are some specialized embedded systems, and these modems are tightly coupled to the overall project design.

I'm not saying that there is a particular "issue" with the PBX, other than perhaps a lack of needed flexibility in this case.

I presume that your 6000 phones all ring as I've described, and in this situation, my requirements are that the phones ring like your home phone (presuming you have Analog POTS service at home).

I've used Brooktrout in the past with Mitel and didn't have any issues, but then again, the Mitel ring cadence was 2/4 and (if I remember correctly) a class-of-service option controlled whether external calls generated a double ring or not.

I suspect that Brooktrout's timing logic was a bit overly restrictive, much the same as I know it is in this situation.

Having designed telcom equipment, I can tell you the reason for being a bit paranoid when it comes to ring detection, is to avoid false positive detections which can occur when paralleled sets go off/on hook and/or during electrical storms where nearby strikes will trigger the ring detection hardware. To combat this, you try to weed out things that don't look like a normal ring signal.

This is one of those "perfect storm" situations where Lucent went one way with their timing, and the modem manufacturer is taking GR-506 compliance a bit to literally.

I'll continue to pursue this with the modem manufacturer, and will also continue to look for answer's on the Avaya side.

Thanks,

Dave,

Dave,

Have you even attempted to look in the manual? :read: I went on the Avaya site and came up with this in about 2 minutes

Dave, if the modems are set to auto answer (ATS0=1), the cadence shouldn't matter since they will answer upon the initial ring burst. Just a suggestion.

ttech,

No, I had not. I suppose the context of 'customer' in my original post probably was not clear enough.

In one sense, it could be interpreted as though our role is that of PBX repair/installation/programming and that this related to something we were trying to accomplish for a customer... but that's not the situation.

What I should more clearly have conveyed was that we are responsible for a system design, which is a consumer of PBX/PSTN resources and that the customer is responsible for providing us with suitable phone lines.

It was never our intention to have to get this intimate with their PBX, but that is what it has evolved (or perhaps devolved) into.

Since my original post, which was based on observations noted during the initial installation, the customer had already made those, and other changes. So perhaps they :read: their manuals...


Since my postings earlier today, I did download what appears to be all of the relevant information from Avaya, and have spent a few hours skimming through it.

If nothing else, I've learned quite a bit about what this thing is, and how it all plays together.

In the end, I guess I've reached the same conclusion that the customer's vendor did, and that is that the flexibility does not exist to alter the ring cadence timing.

Thanks,

Ed,

...yes, the modem's are configured for auto-answer.

The modem's firmware is clearly responsible for qualifying what it thinks is a valid alerting signal, and what is not. In this particular situation, the modem's are expecting a ring cadence based upon north American Central Office standards (i.e. 2000ms on, 4000ms off).

This evening, I used a DSO (digital storage oscilloscope) to measure the PBX's ring cadence and measured 981ms on, 4046ms off.

Based on my earlier observations, I suspect that the on time is about 20ms shy of meeting the modem manufacturer's current expectations.

I also checked the RI (Ring indicate) output, and it never transitions when ringing is present, which again confirms that the modem's timing expectations are not being met.


As I mentioned in an earlier post, these modems are some rather specialized units, and are targeted towards an industrial controls market.

We have some of the first production units for our proof of concept project.

I suspect that most other modem manufacturer's learned long ago to relax their ring detect timing to accommodate a broader audience, however this European manufacturer has taken a more literal approach to standards interpretation.

On a CO trunk, they answer just fine.

Thanks,