We run a range of Vigor routers, including 2866ac/Lac, 2865ac/Lac, 2862n plus a few other models at 80 plus remote locations.

At the moment each location has a single telephone that run on conventional landlines although we are planning to switch to a VoIP system across the company in the medium term. In the meantime, however, we have several PSTN contracts due to expire in the next 6 months which we're considering switching to Sogea.

What I'm trying to find out is whether we need to upgrade the routers (again) to one of the V versions or if there is someway of using the existing telephones through the router using some kind of analogue adapter.

Any suggestions/advice please?

Hi Gary, this can get very complicated very quickly.

The simple answer is that SOGEA is broadband over the wire only, no telephony service.
It's down to the provider as to how they implement it, obviously VOIP is the most popular.

Some will insist on using their router with telephone socket built in, others may release the details to you.
The benefit of it being on the router however is that the ISP should prioritise the VOIP, whereas you'll have to try and replicate the setup on the Draytek if you want the same.

VOIP gateway is what you're looking for.
https://www.amazon.co.uk/Topiky-Internet-Adapter-Gateway-Linksys-UK-Plug/dp/B07SKV4255/ref=sr_1_5?keywords=voip+adapter+uk&qid=1694175720&sprefix=voip+ada%2Caps%2C122&sr=8-5