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[snadge]

yipee 

just how effective is that bellwire filter I wonder... its probably best that even someone using the SSFP should probably remove the bellwire just for good measure I think

Im glad you put me onto that VDSL Faceplate - that will be the one I recommend to people now as its easier to fit (for those worried about removing wires etc)

am I right in saying that if your internal wiring introduces noise and you use a FFP to terminate the xDSL at the NTE-5 that the interference can not travel back through the filter and into the xDSL signal..?


thanks for answering all my questions...

[burakkucat]

its probably best that even someone using the SSFP should probably remove the bellwire just for good measure I think

That's exactly what I do. It's extremely rare for that wire to be required, these days.

am I right in saying that if your internal wiring introduces noise and you use a FFP to terminate the xDSL at the NTE-5 that the interference can not travel back through the filter and into the xDSL signal..?

That is the general principle, so "yes", once again.

Now consider the case of a person who has an xDSL service provided over an Openreach maintained metallic pair but never uses it for telephony. In that case, no filter is / filters are required. The modem/router can be plugged directly into the NTE5/A via a suitable adaptor or if that is not a convenient location, a twisted pair Cat5e extension can be run from IDC3 & IDC5 at the NTE5/A to a RJ11 socket fitted elsewhere.

[HPsauce]

wonder why he changed his name...

Probably best not go there.......... 

[waltergmw]

@ BKK,

1.  Sorry I overlooked replying earlier. The SSFPs were both the ADSL V 1.0 type

2.  Re your latest post, I don't think you can prevent every cold caller but I'm unaware what effect that might have on an ADSL cct without a phone connected ?

Kind regards,
Walter

[burakkucat]

@Walter -- Thank you for clarifying the version of the two filters that went U/S.

As for your second point, the answer is none. Consider what happens when a call is initiated to any line. A (time modulated) AC voltage is applied across the pair. Acceptance of that occurrence was built into the initial ADSL standard . . . which continues into the current VDSL2 standard.

I have not done so but that could be an interesting experiment. Ideally one would use a dual "beam", storage O'Silly Scope.    Connect channel one to the xDSL output from the SSFP and connect channel two to the telephony output. Call the relevant telephone number for the line from a mobile phone and adjust the trigger level, channel gains, etc. What is seen?

Could somebody perform that experiment, please?  Perhaps Eric or Asbokid? (I only mention those two names because I have a very strong suspicion that they both own an O'Scope.)

[roseway]

I would love to do the experiment, but unfortunately I parted company with my last oscilloscope a couple of years ago.

[asbokid]

@Walter -- Thank you for clarifying the version of the two filters that went U/S.

As for your second point, the answer is none. Consider what happens when a call is initiated to any line. A (time modulated) AC voltage is applied across the pair. Acceptance of that occurrence was built into the initial ADSL standard . . . which continues into the current VDSL2 standard.

I have not done so but that could be an interesting experiment. Ideally one would use a dual "beam", storage O'Silly Scope.    Connect channel one to the xDSL output from the SSFP and connect channel two to the telephony output. Call the relevant telephone number for the line from a mobile phone and adjust the trigger level, channel gains, etc. What is seen?

Could somebody perform that experiment, please?  Perhaps Eric or Asbokid? (I only mention those two names because I have a very strong suspicion that they both own an O'Scope.)

Hi.. I've got a dual channel DSO.. Very happy to have a look but not sure I understand what's required here though...   What is the test intended to discover? Whether there is any evidence of the ring voltage appear on the xDSL side of the splitter in the faceplate?

We have only got a bog standard NTE5 (plus microfilters) here, although I recall buying an SSFP (after we chatted about the depth of them some months ago).. Where it went is anybody's guess 

It struck me that noone (to my knowledge) has published results of comparative tests of any line filters, both the discrete devices and those integrated into a face plate.  Wouldn't it be a very easy experiment to set up with a scope and signal generator?

cheers, a

[burakkucat]

I would love to do the experiment, but unfortunately I parted company with my last oscilloscope a couple of years ago.

I wonder, was that due to necessity (space requirements) or the just 'scope reaching the end of its useful working life?

b*cat makes a mental note to decouple Eric's name from the O'scope list.

[burakkucat]

Hi.. I've got a dual channel DSO.. Very happy to have a look but not sure I understand what's required here though...   What is the test intended to discover? Whether there is any evidence of the ring voltage appear on the xDSL side of the splitter in the faceplate?

It's not to discover anything but just to show to Walter that the "ringing" voltage will appear on the xDSL output from either a centralised filter or a microfilter and, thus, his earlier concerns about plugging a modem/router directly into the NTE5/A, without any filter, are quite unfounded.

It struck me that noone (to my knowledge) has published results of comparative tests of any line filters, both the discrete devices and those integrated into a face plate.  Wouldn't it be a very easy experiment to set up with a scope and signal generator?

Do I detect that another project has just been added to the asbo-ToDo list? 

[asbokid]

Hi.. I've got a dual channel DSO.. Very happy to have a look but not sure I understand what's required here though...   What is the test intended to discover? Whether there is any evidence of the ring voltage appear on the xDSL side of the splitter in the faceplate?

It's not to discover anything but just to show to Walter that the "ringing" voltage will appear on the xDSL output from either a centralised filter or a microfilter and, thus, his earlier concerns about plugging a modem/router directly into the NTE5/A, without any filter, are quite unfounded.

aha.. that's pretty much how things are wired in asboville.  although to up the ante, the modem has been permanently plugged into the test socket for some months now :-)

It struck me that noone (to my knowledge) has published results of comparative tests of any line filters, both the discrete devices and those integrated into a face plate.  Wouldn't it be a very easy experiment to set up with a scope and signal generator?

Do I detect that another project has just been added to the asbo-ToDo list? 

an ever growing list.. sadly with more pressing priorities including the tax return to complete, a faulty airbag circuit to repair in the car (now an instant MOT failure point) and of course the never-ending 2wire project!

on the tdr project though.. it would be fascinating, as Eric has already noted, to create some consumer wiring arrangements for testing the presence (or not) of signal reflections from the unterminated/badly terminated/properly terminated "branches" of consumer wiring extensions.. 

cheers, a

[roseway]

I wonder, was that due to necessity (space requirements) or the just 'scope reaching the end of its useful working life?

Me, not the 'scope.

[burakkucat]

I wonder, was that due to necessity (space requirements) or the just 'scope reaching the end of its useful working life?

Me, not the 'scope.