1) BT/BT Wholesale now recognize landline numbers from other VOIP providers and will allow you to transfer the number back to BT (no idea about other ISPs), either to copper or to Digital Voice. I'm actually in the process of porting my yay.com VOIP number back to BT Business on Digital Voice as I'm forced to take out BT's voice service with FTTP whether I use it or not. So might as well save a few ££ each month by cancelling my yay service and use BT's voice service instead.

2) The ATA adaptor normally plugs into your router at one end and into your regular phone on the other end. I'm using a Grandstream HT801 ATA with yay and have a DECT handset/base plugged into this, with other DECT handsets placed around the house where required. However once I start using BT's Digital Voice service (aka Cloud Voice Express) then I'll simply plug BT's VOIP handset/base station into my router. Though I will need to ask them for additional handsets as they only provided me with 1 base & 1 handset:

https://btbusiness.custhelp.com/euf/assets/cloud_voi...

3) Sorry no idea

As I asked before, which phones do you currently have?

You might want to take a look at the Gigaset products.

The ones with IP in the name combine a conventional POTS base station and 8 VOIP accounts. I've used one for over 10 years for our main landline (we ported our old BT number in 2007 when moving to a nearby village - BT couldn't do it so we just moved it with us on VOIP) and it works very well indeed.

I had played with Frtizboxes and separate ATAs for a few years beforehand. They all work, but the Gigagset idea is very simple and a completely transparent, single box solution for normal users.

If you need to use your existing wired handsets though you'll need an ATA as posted above.

It is only 6 VOIP accounts - plus PSTN plus Gigaset.net


They also tens to sell them as the S850 GO or S410 GO or similar. Reason I have asked te OP about their existing is if they have wirelss phones they may well be DECT complaint and would work with an N300 IP or N300A IP

In reply to a post by FibreFelix:

Thank you Nick. That's actually very useful. Should it 'just work' with the extension wiring if I remove the main phone line connection to the master socket? The more I look into this however I wonder if it's just a lot less hassle to buy some Dect phones!

I am using a Cisco122 connected to a phone extension socket with the phone disconnected from the master. We have a mix of Dect and analog handsets and it all just works.
One caveat though to get a dial tone you will need a short adapter cable with a ring capacitor plugged into the Cisco's RJ11 phone socket and then a BT to BT cable to hook into the extension socket.

In reply to a post by MHC:

It is only 6 VOIP accounts - plus PSTN plus Gigaset.net


They also tens to sell them as the S850 GO or S410 GO or similar. Reason I have asked te OP about their existing is if they have wirelss phones they may well be DECT complaint and would work with an N300 IP or N300A IP

I use the Gigaset N300 IP and C430 Dect handsets. I could no doubt make a phone call with another brand of Dect handset, but many advance features such as transfering telephone directory entries tend not to work.

I find the answer phone features of the VOIP providers such as Sipgate and Voipfone whereby I get a text message and email with a sound file, much more useful than an answer phone facility of my own.

First you need to check whether you can port your number without closing your current FTTP connection. When I ported my number to Sipgate from Plusnet FTTC that trigged a termination of my copper line which was fine because by then I had an FTTP line active.

I use a CISCO SPA122 connected to a wireless access point in my office with one port connected to a conference phone and the second to a BT DECT base with five phones around the house. I can make/receive a call on my conference phone while the DECT phone is in use which can be useful.

I moved to Sipgate because there is no monthly charge and the call rates are low from around 1p per minute or you can subscribe to one of the unlimited call packages. I also get voicemail sent as email and you can block numbers on the web interface - this also shows you your call history.

In reply to a post by MHC:

It is only 6 VOIP accounts - plus PSTN plus Gigaset.net

Quite right! - I should have double-checked - slip of the memory. I can't now edit the original post to correct it now.

I use a 750GO these days and thought I had mentioned GAP compatible handsets work with these base stations - but clearly didn't!

Looks like OP has enough to be going on with now.

Edited by albany11 (Mon 15-Jun-20 09:23:51)

Good Afternoon Everyone!

Firstly, thank you all for your suggestions! I've now managed to order a service from Vonage as they provided a free ATA as part of the service. I may change in a year or so to SIP gate but I have no complaints with Vonage at all.

I've managed to plug the ATA directly into our Unifi Switch and it worked immediately. I then plugged in our Panasonic Dect Phones and I had a dial tone right away and could make calls. I answered my own question in that if someone is on the phone and another picks up another DECT phone they can hear the conversation (at least on our handsets anyway!).

I gave up trying to use the extension wiring and instead whilst the phones get signal just about everywhere (although in some places they say zero connection to base station despite working), I think I'll order a Powerline Adapter to place the DECT dock in the middle of the house rather than the cupboard the networking equipment is in.

As an aside, I particularly like with Vonage that it transcribes the voicemails left and emails them to us! Much easier!