In reply to a post by mrwrighty:

Half the battle in supporting 3rd party VOIP hardware such as a grandstream would be getting the VOIP settings and credentials from ZEN. If this isn't forthcoming then I'm stuck. The actual configuration doesn't faze me, just the availability of such information to make it work.

Then don't get VoIP from Zen. Superficially it looks simpler to take telephony from your ISP, but it is a world of complication when you want to change ISP. There are plenty of VoIP service providers out there and provided you avoid CGNAT ISPs, changing ISP does not affect your telephone service.

I can’t separate them. TalkTalk will not let me separate them as it’s linked to my FTTP account, moving my phone line from TalkTalk will cancel my FTTP service, yes true even though the landline is still on copper. ZEN will take over the FTTP and my landline, but I have to keep both with them for the duration of the 18 months contract as confirmed by a phone call from their sales team.

In reply to a post by mrwrighty:

I can’t separate them. TalkTalk will not let me separate them as it’s linked to my FTTP account, moving my phone line from TalkTalk will cancel my FTTP service, yes true even though the landline is still on copper. ZEN will take over the FTTP and my landline, but I have to keep both with them for the duration of the 18 months contract as confirmed by a phone call from their sales team.

You can break that logjam by ordering a new FTTP service (not a take over of an existing service) from Zen without any phone element then once you are happy that is working you get a VoIP provider to take over your phone service. The VoIP provider will trigger the cessation of your TalkTalk service but you already have the Zen FTTP up and running. The downside is one or two months of double cost while you run TalkTalk and Zen in parallel.

Then I have 2 fibre connection to the house, the old one will never be removed and 2 x ONT installations, yes an option, but not one I will be taking.

An ISP who knows what they are doing could request a replacement ONT with four ports so you only have a slightly larger ONT but still a single box on wall / power supply / fibre connection to the premises.

In reply to a post by tdw42:

An ISP who knows what they are doing could request a replacement ONT with four ports so you only have a slightly larger ONT but still a single box on wall / power supply / fibre connection to the premises.

There was a time when some ISPs had an issue with providing/taking over a FTTP service on anything other than the first port, does anyone know if that issue has been resolved now?

Hi DazColl,
Did you ever resolve this?

Reviving an old thread, but if anyone is still facing the migration to Digital Voice, here's a solution not involving a Fritzbox at all.
Having been a Zen customer for over 20 years, I was upgraded yesterday. We're in a remote part of the Pennines and FTTP is not available, so I was moved to a SoGEA connection. I've always used Draytek routers, and being a tight *rse, I was not looking to spend any money! I already had a Cisco SPA112 VoIP adapter, handling an old number ported several years ago to Voipfone. This is a two port adapter, so following the guides below, I configured the second port with Zen's SIP settings. With appropriate firewall rules in place on the Draytek (see James Batchelor's walk through), it's working with my existing cordless phone system connected.

Guide to Zen DV & Draytek - https://james-batchelor.com/index.html%3Fp=965.html

Guide to Zen DV & softphone - https://www.aligrant.com/web/blog/2025-11-12_zen_sip...

Zen SIP settings - https://www.zen.co.uk/help-support/general-sip-setti...

Hope that helps someone.

Cheers.

Since moving to ZEN and been given a Fritzbox for VOIP which I quite like as it handles the voicemail and emails me a copy, I have put the Fritzbox in a DMZ on my Unifi network (UDM Gateway) and port forward 5060 and all works as expected including voicemail, emails, call log history etc.

Edited by mrwrighty (Wed 16-Sep-26 15:21:06)

Like many others I'm having an issue with getting Zen's VOIP to work properly. In this case I'm using a Draytek 2860 and Gigaset Phone. Seeing that others have got this working there may be some advice here that could get this working properly.

After much research and wireshark packet captures it seems that I'm hitting the problem with the Draytek, that another poster has mentioned, sending UDP packets from a port number that Zen does not expect. As a result an incoming call will ring but the message that the Gigaset has gone off hook does not reach Zen's SIP systems.

Any pearls of wisdom most welcome.

Thanks - Ken