This topic

Duplexing analogue phones on digital voice service

JayKayGee — Sun, 16 Jun 2024 10:28:11 GMT

Hello, is it possible please to duplex (non dect) analogue phones on my digital voice service, such that an incoming call on one handset can be picked up on the second handset?

I have an SH2 and FTTC. My analogue phones (one new, a BT model and one older manufactured in 2008) are plugged into the hub and a DV adapter respectively. The new one plugged into the hub doesn’t start to ring until 3 rings after the older one plugged into the adapter (I’m told this is because they are different models.) Whichever handset is used to answer a call, picking up the other handset results in a dialling tone.

I’ve looked into the ‘multi call’ feature of the digital voice service on the assumption that if I disable this I can use both handsets to receive a call, but it appears to relate to digital handsets only (has to be disabled on them) so has nowt to do with my problem.

I’ve seen it may be possible to reinstate my old telephone extension wiring (which allowed analogue handsets to take over or join the call when lifted) but I’d rather avoid fiddling with the wiring (and I’m confused about the extension box setup). But is this or dect handsets the only way to get hanset duplexing back please? (Does duplexing between digital handsets work?).

Thank you.

Re: Duplexing analogue phones on digital voice service

jac_95 — Sun, 16 Jun 2024 10:42:39 GMT

Hi JayKayGee,

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Re: Duplexing analogue phones on digital voice service

imjolly — Sun, 16 Jun 2024 10:47:40 GMT

you might find this older post helpful https://community.bt.com/t5/Home-phone-including-Digital/Multi-call-option-Digital-Voice/td-p/2314704

Re: Duplexing analogue phones on digital voice service

JayKayGee — Sun, 16 Jun 2024 19:05:35 GMT

Thanks. I had a look at the FAQs, tried various searches through the forum topics and did a good bit of reading before posting, but didn’t identify the thread you pointed to. I’ll study it now in the hope it provides an answer.

So far on a quick read I think I have gained an understanding of why an extension box next to the master socket is needed to reinstate the original extension sockets to working order (for FTTC) and this is becoming a possibility to get the function I want back.

I thought I’d managed to switch off multi call on dv but I need to revisit this. Interesting that the other poster identified it as a contributory issue, as I did.

Thanks again

Re: Duplexing analogue phones on digital voice service

licquorice — Mon, 17 Jun 2024 08:50:40 GMT

It is not multi call causing the problem. See messages 19 and 20 in the linked thread.

The green hub socket and dva adapters appear not have connectivity between them.

Re: Duplexing analogue phones on digital voice service

JayKayGee — Mon, 24 Jun 2024 22:12:03 GMT

Thank you for your observation that the green socket on the SH2 and the BT implementation of DECT (viz the adapters) appear to have no connectivity. This is my conclusion also after trying different options. I guess the BT dect implementation works uniformly across BT digital handsets and their phone adapters, but the socket is a separate (physical?) input.

What this means in practice is that for a 3 handset setup to have duplex I should go for (1) a dect set with three handsets and the base station plugged into the SH2; (2) three digital handsets which would allow transfer between them using the functionality they provide; or (3) hook my old extension sockets up to the SH2 as described in other threads. Cost is a factor in the first two options so I am trying to sort out the existing wiring hookup. Mixing methods (bt-dect and SH2 green socket) will never give me full duplexing.

I’ve tried linking the SH2 green socket to the wall (master) phone socket with a ‘straight through’ male to male plug cable and got my analogue phones to ring when plugged into the old extension sockets. However I didn’t get duplex between two handsets and there was a lot of line noise. So should I be using a ‘crossover’ male to male cable please?

Also, this was without disconnecting anything in the master socket. As the three wires serving the phone port in the master socket already appear to be isolated from the wiring relating to broadband, I don’t understand why its necessary to disconnect them and ‘move’ them to a new old style extension socket box. (The three phone wires in the master socket are red, blue and grey crimped into terminals labelled 2, 3 and 5 respectively and afaik have no functionality now except to serve my extension cabling.) Sorry if I’m being thick but if I do have to move them I’ve got to work out how as they are not sheathed and not very long.

Final stupid question; can I use a phone socket doubler on the master socket (or the new extension socket if needed) and plug in both an analogue phone and the SH2 (via a male to male cable) and still get my full duplexing please? Or does the analogue phone have to be plugged in ‘downstream’ of the SH2 connection into to my extension socket wiring?

Thanks very much for any help you are able to give on these questions, I really appreciate contributors giving up their time and probably having to repeat themselves to help people like me, and frankly I am not as sharp as I was in the days of dial up internet and uudecoding of downloads (yes I am that old).

Re: Duplexing analogue phones on digital voice service

Anonymous — Tue, 25 Jun 2024 06:31:18 GMT

The simplest way to isolate the wiring is to remove the faceplate from the master socket. You will then need to use a micro filter to connect the SH2 to the test socket for internet. This should work & you can then decide whether you want to tidy up by installing a second socket just for phones. If the extension wiring runs along the skirting you can disconnect it & place the socket a little distance away from the current master to give you more room to play with. But if it's buried in the wall you'll need to extend it somehow.

Re: Duplexing analogue phones on digital voice service

JayKayGee — Tue, 25 Jun 2024 08:28:22 GMT

Thank you. The wiring to the master socket is a black cable running on the outside of the house and passes through the wall straight into the back of the master socket. Its taken from the old master phone socket (pre broadband) in the hall and moves the connection to a different room. Interestingly I found when I took the faceplate off the master socket, my broadband connection went off. This wasn’t what I expected as the cable linking the hub to the faceplate stayed in place and the front data socket it plugs into has a cover behind it, so no broadband wiring was disturbed. I guess the faceplate connects to the broadband wiring in the back of the master socket via the plug and socket affair behind the faceplate. Which is why I think the telephone wires are already isolated ……

Think I need to try a crossover male to male cable. I’ve seen hints that a direct SH2 green socket connection to the master socket mucks up the broadband signal and this worries me, but I guess I just have to try it.

Thanks again!

Re: Duplexing analogue phones on digital voice service

Anonymous — Tue, 25 Jun 2024 08:41:47 GMT

Please read what I wrote.

Re: Duplexing analogue phones on digital voice service

JayKayGee — Tue, 25 Jun 2024 09:17:40 GMT

Thanks. I need to go back to the shed to find a microfilter. (Haven’t had to use one since the master socket was installed maybe 15 years ago). I’ll report back once I’ve tried what you wrote.

Re: Duplexing analogue phones on digital voice service

JayKayGee — Wed, 31 Jul 2024 14:21:56 GMT

Well, I have finally got my old analogue wiring connected into digital voice such that handsets ring in tandem and they can be picked up in the different rooms and join/take over a call. It was both easy and complicated so I provide notes for anyone wishing to do the same.

Mine’s is an old installation put in between 2007 and 2017 (based on the vdsl master socket type in place). I have FTTC meaning 2 wires (‘copper’ ) come into the house to a small junction box, which is wired through to an old BT master phone socket in the hall, the two wires (via jelly crimps) then being cabled to a wire to an NTEC5 master socket (type A) at the back of the house. This same cable takes three wires back to the hall master socket where they are idc crimped into the old phone master socket. This provides the wiring to my analogue phone extension points.

After DV switchover the telephone socket on the vdsl master socket no longer provided telephone service, and my old extension sockets were also dead.

To reinstate things, I disconnected the three telephone wires in the vdsl master socket (which had been inserted into a 3 pin idc block on the face of the cover) and jelly crimped them to three wires in a length of phone extension wire. The other end of this extension wire was connected in the matching colour /post number sequence as had been in the vdsl terminal block. This was to a double telephone socket wall plate with a back box. In effect I moved the three telephone wires from the vdsl master socket to an extension box, thus fully isolating my internal telephone wiring from any vdsl master socket connection.

I didn’t know whether to use a telephone slave or a telephone master wall plate (which has extra capacitors and resistors in it) for the extension box. So I tried both and found it made no difference.

I then used a double bt-phone plug-ended cable to connect the green phone socket on the back of the smart hub 2 to my extension box. This was a straight through cable sourced from *bay. I didn’t know whether it should be a crossover cable or straight through cable. I picked the latter and don’t know what difference it would have made.

I then plugged my analogue desk phone into the other extension box socket.

Success! I now had a dial tone on all 3 of my analogue phones and they rang in tandem for an incoming call. However there was a noticeable amount of noise on the phone line. I checked all my cable connections without resolving this so swapped my desk phone back to the direct hub connection (losing my other phones of course).

I read that improvements in filtering were introduced by later vdsl master sockets than mine, so decided to try a vdsl microfilter sold by a specialist telephony bits supplier. When it came I plugged it into the green telephone socket of my smart hub 2 and the bt plug to bt plug cable from there to my extension box. It didn't solve the noise problem however. At this point I thought the problem must be in the vdsl master socket, even though the telephone wiring was now separated. So I resolved to try the vdsl microfilter in the test connector of the vdsl master socket but before I could do so my broadband service download speed crashed from around 30Mbs to 2Mbs. I called the service line to see if there was a service outage, the BT Guide checked settings and made some adjustments (didn’t say what) and offered to send an Openreach engineer around to check my installation. Two days later he came, installed a new vdsl master socket (mark 4 type) without me asking and replicated my extension box for the telephone wiring. Thereafter all has been fine, same broadband speed as before and analogue telephones all working with no line noise. Hurrah!

I want to give my thanks to the contributors to this thread @licquorice , @imjolly , @jac_95 , to the Posters in other threads who provided the method, to the Openreach engineer and to the BT Guides, all of whom have helped me to the solution.

I recommend if you are in a similar situation, your also reach out for the help on offer.

Re: Duplexing analogue phones on digital voice service

JayKayGee — Wed, 31 Jul 2024 14:28:37 GMT

Apologies @Anonymous , I overlooking name checking you in my thanks list. Here are my thanks now.