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Message 1 of 4

ADSL Micro Filters, the ring wire and Digital Voice

It has been a bit of a learning curve switiching to DV.

I am pleased that it worked first time from switchover some months ago.

I have a an Essentials DV handset and also a DV adapter.

There are two older MF capable phones (Viscount and Tribune) that I still love to use and both ring ok when plugged into the SmartHub phone socket.

When these older phones are plugged into the DV adapter they do not ring - and as found out elsewhere on the forum that is due to no 'ring wire' being present on the DV adapter phone socket. To fix this you can use an ADSL Micro Filter.

A friend gave me an old BT ADSL Microfilter and this worked perfectly - bells now sound on any older phones when plugged into the DV adapter.

I also have an old CD 1000 caller display unit. This also requires the use of an ADSL Micro Filter to get that to work on a DV Adapter and indeed on the SmartHub phone socket.

Needing a further ADSL Microfilter I purchased one from Amazon. That did not work. No ringing or CD info. Tried a different make again from the Amazon site but a bit more expensive. That also did not work. Sent those back for a refund. I then saw a more expensive one at Argos - thinking it must contain more components and maybe the extra capacitor to provide the ring wire. Alas no, that one did not work either.

I then saw what looked like a proper BT ADSL Microfilter advertised on the RS Components website. It cost £11 odd plus VAT and delivery. I bought that and hey presto it does work.

Seems that not all ADSL Microfilters are made the same.  Beware!

Message 2 of 4

Re: ADSL Micro Filters, the ring wire and Digital Voice

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Message 3 of 4

Re: ADSL Micro Filters, the ring wire and Digital Voice

I've found exactly the same thing, but out of three old phones plugged into DV adapters, 2 will ring when plugged in through old integral ADSL filters (no flying leads), but one won't ring at all, with or without an ADSL filter.
I then tried using newly purchased ADSL filters with flying leads, because they are neater. One of the above two telephones rings when plugged into this new filter, but the other one doesn't.
I guess none of this really matters, since I have got two telephones on two DV adapters to ring OK, but I'd quite like to understand these quirks!
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Message 4 of 4

Re: ADSL Micro Filters, the ring wire and Digital Voice

As a follow up to my previous post - I've found that the two new ADSL "flying lead" microfilters that I purchased from Amazon do NOT have inbuilt capacitors. That is why one of the phones connected via one of these filters does not ring.

So why did the other phone connected via the other new filter ring OK? That's because I connected it via a new BT socket (to feed from the DV adapter into some now redundant house extension wiring) and that socket has a capacitor in it (again not all BT sockets that you can purchase have this capacitor).

Although you can normally see from the pictures online whether a BT socket has a capacitor, you can't tell just by looking at them whether ADSL filters have a capacitor - so it's pot luck when buying these!

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