Using a phone with a Digital Voice Adapter

[redders22]

I've just had full fibre (FTTP) installed with Digita Voice. I wanted to use my existing phones (geemarc amplidect 595) as they are designed for the hard of hearing. I connected them up to the green phone port on the smarthub2 and all works fine (no problems). However my problem is, along with the geemarc phones I had a "normal"/corded phone in one of the bedrooms. I tried to connect this corded phone up to the Digital Voice via a DV Adapter. When I rang my number all the geemarc phones rang but the normal (corded) phone didn't. Although it didn't ring, I can answer an incoming call using it and also dial out using it (if I pick it up I do get dial tone).

Any thoughts on this/can anybody help?

[jac_95]

Hi redders22,

Thanks for the post and welcome to the Community.

This is an automated response as I can see you have a question about BT’s Digital Voice service. Rather than waiting for a response from the Community, you may find an answer to your question by using the search bar on the Community homepage. We also have a thread that contains a wealth of info related to BT’s Digital Voice, click this link to take a look, Digital Voice FAQs.

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[Keith_Beddoe · Accepted solution]

@redders22 

Welcome to this user forum for BT Retail phone and broadband customers.

The DV adapter only presents a two wire connection, and some phones need the additional "bell" wire to ring, i.e. three wires.

The missing third wire can be emulated by plugging a microfilter into the socket of the DV adapter, and then plugging the phone into the "phone" socket on the microfilter.

The microfilter has an internal capacitor which extends a third wire from the existing two wire connection.

[redders22]

@Keith_Beddoe    Thanks for the reply/suggestion. Just tried it and it works perfectly. Once again, thanks for your help.

[Keith_Beddoe]

Its probably why BT say that some older phones will not work. But as you can see, its an easy fix.

[dwatki]

Nice work round to answer the incoming ring problem.

Interesting that the socket on the rear of the Smart Hub does not have the incoming ring problem. It must have a capacitor fitted. 

Presumably a 2uF capacitor fitted in the instrument would also function. Bell wiring was always a problem in the old days. 

[licquorice]

In the old days, bells were wired in series whilst the speech circuits were wired in parallel. Extensions are all in parallel these days.

[Keith_Beddoe]

And the rotary dials had a "dial off normal" contact which short circuited the bell wire, so all the bells did not tinkle when someone dialled out. The later "Trimphone" which was a two wire appearance, had a thermistor inside to suppress any "pips". These of course failed whenever there was a storm. Replaced lots of these when I was a TTA (Trainee Technician Apprentice) 1968. 

[chrisjp]

It's a shame BT doesn't fit a capacitor into its digital voice adapters. Then all phones would work properly with them, rather than having to mess around with connecting via ADSL filters - and finding such filters that have capacitors in them - which is not all of them.

[dwatki]

It would appear there is a capacitor in the "Green" jack on the Smart Hub. So no problem with incoming ringing if using the Smart Hub direct.

As pointed out in this thread it is the absence of a capacitor between connections 5 and 3 on the output from Digital Voice Adaptor (DVA) that causes the analogue instrument incoming ring to fail.

If the excellent suggestion of the ADSL filter jack does not work, or the prospect of an additional item being plugged into the DVA does not appeal, there is a work round involving the telephone instrument.

The work involved would be relatively simple but could only be undertaken if the instrument is owned by the individual. It would require the disassembly and subsequent reassembly of the phone. Requires some experience and not for the faint hearted.

Normal wiring of the connection cord of a simple telephone has 4 wires terminating inside the instrument, Red,Blue, Green and White. Red and White carry the speech signal. The signalling (Ringing) is on the Blue wire. A capacitor connected across the Red and Blue terminations in the telephone instrument solves the incoming ring problem. There may even be a redundant capacitor in the 'phone but this would require some technical knowledge to locate.

It is over 25years since I was involved with analogue telephones but little changed between the tele 150 and the last phones on the PSTN.in the UK.