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TOPIC: Are ADSL filters required if you are not using it for Voice?

Are ADSL filters required if you are not using it for Voice? 10 years 4 days ago #18534

  • Smurf
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So, just got off the phone with an ISP who will not do any fault diagnosis with me on my ADSL line which keeps disconnecting every afternoon. The Debug on the Cisco routers seems to suggest that the issue is at the ISP end because we get as far as PPP "No Remote Authentication for Call-Out" and then it goes into LCP stuff instead of then starting a CHAP challenge.

Anyhow, I have been told that before they can log this with BT, i will HAVE TO install a filter, even though we do not have a telephone plugged into the phone line since its only used for ADSL.

Am i right here in that if you are not using voice over it, why do you need to split the frequency for Voice and Data ? Doesn't make any sense to me ?

Cheers
Wayne Murphy
Firewall.cx Team Member
www.firewall.cx

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit www.sec-1.com or PM me for details.
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Re: Are ADSL filters required if you are not using it for Voice? 10 years 4 days ago #18535

  • DaLight
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As far as I understand, the filter simply blocks the lower frequency components of the signal required for voice and allows the higher frequency components through to your modem (and the reverse for your phone)

I would think if you had to use a filter without a phone connected, you probably have other issues.

However, I stand to be corrected.
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Re: Are ADSL filters required if you are not using it for Voice? 10 years 3 days ago #18569

  • TheBishop
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I always thought the filter was for the phone's benefit rather than the modem. However there's a simple remedy; just stick a filter in, prove the fault is still there and then call them out! If you need to borrow a filter I've got a spare so give me a shout
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Re: Are ADSL filters required if you are not using it for Voice? 10 years 3 days ago #18572

  • Smurf
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If you need to borrow a filter I've got a spare so give me a shout

Cheers for the offer but one of the lads at work has a spare one to just test :)
Wayne Murphy
Firewall.cx Team Member
www.firewall.cx

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit www.sec-1.com or PM me for details.
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Re: Are ADSL filters required if you are not using it for Voice? 10 years 3 days ago #18606

  • GTM
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If you are getting dsl on your router which i gather you are as you are getting to the ppp stage which means you are synced up with the isp's line then a microfilter wont make any difference as the problems an authentication issue not a physical connection one.
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Re: Are ADSL filters required if you are not using it for Voice? 10 years 2 days ago #18619

  • Smurf
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If you are getting dsl on your router which i gather you are as you are getting to the ppp stage which means you are synced up with the isp's line then a microfilter wont make any difference as the problems an authentication issue not a physical connection one.

Thats a very good point, if i am getting PPP on layer 2 then layer 1 must be ok :)
Wayne Murphy
Firewall.cx Team Member
www.firewall.cx

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit www.sec-1.com or PM me for details.
The administrator has disabled public write access.
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