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Caller Line Identification - does it work with ADSL filter in place

mal0z
Community Veteran
Posts: 3,486
Registered: ‎02-10-2008

Caller Line Identification - does it work with ADSL filter in place

I'm just wondering if CLI displays still work when you have an ADSL filter on the line.
I seem to recall that the signalling might be higher than 4kHz and so could be filtered out ?.
Years ago we used to get CLI for free - I remember buying a phoned that displayed caller numbers about 1997.
Sadly these days this is an a chargeable option, rather strange when it is standard on all mobile phone networks.

9 REPLIES 9
Anotherone
Community Veteran
Posts: 19,107
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Registered: ‎31-08-2007

Re: Caller Line Identification - does it work with ADSL filter in place

Yes Mal, it does work, however some cheap filters can stop it from working. It might in such circumstances also be related to how far you are from the exchange and how sensitive the particular  CLI receiver is.
Quite agree with you about the charge, but that's BT for you - you have to pay extra for virtually all the additions that the latest technology has brought. Landline telecomms (was only BT, and still dominated by BT as we know) is about the only hi-tech arena where this is true. (cf. colour tv - when it came in you could get a good quality colour tv, mostly valve, for around £400. The same is true today, but look at the extras you get - remote control, teletext, LCD, and the reliability (generally) of solid state technology and now digital. [Note if you are a BT subscriber - line rental - you can get it for free as long as you make some calls with BT, although it wouldn't surprise me if they suddenly insisted that you pay by monthly DD as well >:(].
jelv
Community Veteran
Posts: 26,786
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Registered: ‎10-04-2007

Re: Caller Line Identification - does it work with ADSL filter in place

I have CLI on my line with ADSL and it works fine.
It's free from BT if you take the BT Privacy at Home package.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£14.40/month)
Mobile: iD mobile (£4/month)
Mad_Moggies
Community Veteran
Posts: 1,255
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Registered: ‎01-08-2007

Re: Caller Line Identification - does it work with ADSL filter in place

You have to pay extra for CLI with BT if you don't make more than a certain number of charged calls with them (ie if you just rent the line and use another company for calls, as we did), same as with them charging for 1571, which they brought in sneakily as an unspecified extra charge on our bills, which we queried, and which tipped us over to moving to PlusNet.
CLI is working nicely here and we have different tunes/ringtones set to play for certain people too so we can hear who's callling as well as see who it is.  Smiley
Plusnet user since November 2003
Unlimited Fibre Extra and Unlimited UK & Mobile Calls
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HPsauce
Community Veteran
Posts: 6,736
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Registered: ‎02-02-2008

Re: Caller Line Identification - does it work with ADSL filter in place

I have both CLI and Call Sign (2nd number with different ring) and TwinTalk adapters to control which phones ring when the different numbers are called.  Crazy
It all works fine with broadband (filtered faceplate type setup).
mal0z
Community Veteran
Posts: 3,486
Registered: ‎02-10-2008

Re: Caller Line Identification - does it work with ADSL filter in place

Thanks guys,
I guess it must use in band AFSK or  DTMF signalling then ?Huh
HPsauce
Community Veteran
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Registered: ‎02-02-2008

Re: Caller Line Identification - does it work with ADSL filter in place

mal0z
Community Veteran
Posts: 3,486
Registered: ‎02-10-2008

Re: Caller Line Identification - does it work with ADSL filter in place

Thanks - so it's AFSK then - there's no carrier to shift so it can''t be FSK
http://en.wikipedia.org/wiki/AFSK
itsme
Grafter
Posts: 5,924
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Registered: ‎07-04-2007

Re: Caller Line Identification - does it work with ADSL filter in place

If you really want to find out how CLI work in the UK go here BT system works differently to most others as it's triggered by the line reversal and sent before ringing. Most other systems send the CLI between the short first ring and the second ring.
mal0z
Community Veteran
Posts: 3,486
Registered: ‎02-10-2008

Re: Caller Line Identification - does it work with ADSL filter in place

Many thanks for that - really useful.
maybe Plusnet would consider having a links page to all technical spec.relevant to their business - be it broadband, telephone etc etc.
Those of us of a more technical bent might appreciate that ???.