CLIP

[jpadie]

Hi

I am having a trouble with some devices (typically german made: AVM and Siemens products) not picking up CLIP information on a France Telecom line. The info is there as other devices receive it.

i have gone through the trouble ticket process with both manufacturers and have got no joy. they accept that there are some "non-standard" issues with french lines. sounds like rubbish to me - i think that the signal may just be too weak for these boxes to pick up reliably.

so: is there a way through this with extra hardware? the AVM box, in particular, MUST be part of the set-up but is there a CLIP pass-thru device or signal booster that could be installed inline on the POTS line that might work for boosting or cleaning the signal?

thanks
Justin

 

[SYQUEST]

Though I am not familiar with French telecom standards/requirements a loop repeater might work. But before you go to that, you might verify that the local loop is not defective. Is there another line at the same location you can test with? This way you have something to compare against and can use in the event you need to open a repair ticket.

Hope this helps!

....JIM....

 

[jpadie]

i will test on another line that is closer to the exchange and see whether that makes a difference.

i don't think there is a defect though, as all my other caller ID devices pick up the CLIP just fine and AVM recognise that france telecom poses them a problem with CLIP reception. FT uses the ETSI standard for CLIP. i don't know about general signalling.

i'm not familiar with a loop repeater but will google for it. would it be the same as a ren booster?

 

[SYQUEST]

Well actually there are two types of repeaters for the local loop. One type is called a loop extender, or DLL (dial long line) and that merely boosts the signalling range of the copper pair. The second is a voice frequency repeater, and it boosts the dB level or voice level to a set value. These are typically 2-wire devices and usually installed in the Central Office. Although they may be found on some customer premises depending on circuit design, etc.

This description is typical of designs in the US PSTN and France Telecom may do something similar.

But back to your problem. The ren booster you mention sounds like a device to extend the "ringing" capability of a given line. That won't help your problem with the CLIP. The CLIP information is a data busrt that is sent from the CO switch to the device that receives the info. This data burst is in the audio range, just like voice. So if the problem is level related, then the only type of fix is boosting the level or making the device more sensitive to capture the data burst.

Now I just remembered a company here in the US called WESTELL. They made or may still make a device called the CyberBlock™ model LCR4002 2-wire/2-wire Line Conditioning Repeater. This device can be installed at the premise and runs on loop current. I have not used one, but this might work if still available, but I don't know if the specifications will work in France. You will need to check this out. You may try googling on the WEB for a source or other info to help you out.

Good luck!

....JIM....

 

[Sympology]

I've dealt with France Telecom before (not inregard to this issue) and they do have their own "interesting" take on signalling. For the life of me I can't remember what it was, but I know we really had to muck around with our systems to get them to work. If I rememeber, it was essentially qsig with a bit of a twist.
If I remember I'll post up what it was.

Not much help I guess.

Only the truly stupid believe they know everything.
Stu.. 2004

 

[jpadie]

all info gratefully received. i don't think signalling is the issue tho - as my bog standard english binatone phones pick up clip just fine. i think the problem is in either a buggy implementation from AVM or there is something in the AVM that disrupts the signal (like an unshielded power source or similar).

since i'm not able to change france telecom (!) and i'm not able to persuade AVM to fix their products (nor siemens), i'm left with trying to find a device that will accept the CLIP BEFORE the AVM box and then pass the call on with CLIP and all to the AVM box. all the CLIP devices i've seen are wired in parallel to the handset. does anyone know of a serially wired device?

 

[ISDNman]

Right, I think the problem is loss or noise.

If you have the equipment to measure noise you should do so. Also, loss.

Also, as alluded to above, verify that the phone works on some lines and not others. If so loss or noise could be the problem. If not, then the problem may be a real compatibility problem.

 

[jpadie]

i too think the issue is noise - coupled with the fact that the AVM is too sensitive to the noise.

my dsl box can measure SNR and attenuation which I guess is not perfect. does that give enough info? if not then i'm happy to invest in equipment if you can point me in the right direction.

 

[SYQUEST]

In the US we measure circuit noise in the analogue realm as "dBrnC" with a noise measuring set or TIMMS. Do you use the same method in France?

Also the DSL data transmission is in another part of the spectrum and I don't think the same methods are used for noise measurements for both types of transmissions. Do you know or is there a standards spec for CLIP and DSL in France. That would probably be your best bet, so you know what to measure and what quantities you would be dealing with.

Does Siemens reference any standards in their documentation or in your conversations with them? Might they provide a method to accurately measure noise?

....JIM....

 

[jpadie]

i fear the civil service mentality of these kind of organisations in central europe would make americans shiver with horror. the concept of service culture exists only in novels...

i will investigate though. hope springs eternal!

many thanks for your collective assistance.

Justin

 

[jpadie]

chaps,

noise looks positive as a diagnosis. i have changed the microfilter to a uk designated variant and the CLIP is now being received intermittently.

i think the signal disturbance is being created by two or more factors:

1. i think the ring-signal wire in the first filter i was using was wired directly to the output (i.e. bypassing the filter). although the ring-signal is not universally used in france any more, i believe that FT still bung a voltage down it for those older installations that still exist. if this is not being filtered then there is the potential of some minor disturbance, i guess?

2. the power supply seems partially to blame. if the power supply is in a four-way strip on its own then the CLIP is received cleanly. if it has any other devices in there with it, life is not so good. i've seen stories elsewhere on the web about the power supply being a culprit and AVM themselves have suggested ensuring it's on its own.

question: is there anything i can do to reduce the effects of this noise? are there dampeners that are easily usable? how about those little magnet things one sees on some cables?

tia
Justin

 

[ISDNman]

Justin,

Yes, you can buy a ferrite "choke" and then wrap the power supply cable through it as many time as you can. This will filter noise on the power supply lead.

Unfortunately you may need to cut the plug off the wire to get it throught the toroid (depending on what unit you can locate).

Good luck