DECT phones and ADSL/VDSL

Are there any known issues, particularly ADSL line-noise issues, when DECT-type phones are used in the vicinity of a user's ADSL line termination and router?

I recently visited a male relative of mine where, in the medium term, I'd advised he upgrade his ADSL line termination and filtering to an Openreach Mk3 filter faceplate setup. (I actually donated an OR Mk3 to him). I happened to notice however that, since my last visit about a year ago, he'd ditched his landline telephone and, at home, was now using a phone arrangement involving a Panasonic base-station and two wireless handsets. I know precious little about such devices but I've presumed them to be what are generally referred to as DECT phones. That being so, are there any known problems when using such phones in the close vicinity of ADSL modem-routers and ADSL line terminations such as the NTE5A/OR Mk3 faceplate, as in his case they'll all be in the same room? I've been wondering whether the wireless frequency of the DECTs could ever interfere with his ADSL signalling.

In due course, the base-station will plug into the BT phone port on the lower half of the proposed Mk3 faceplate setup, and his router will plug into the RJ45/RJ11 port on the top half.

On these forums some good few years ago, I thought I once read about interference problems on ADSL lines when using DECT phones. Did I imagine that, or are there any, in fact? I don't know the model name of the Panasonic station/handsets but they're something he bought new not long ago.

It's just that he's always complaining about his long line back to the exchange and therefore poor speeds. But could use of his DECT phones worsen his ADSL SNR and cause his line to work even slower?

I've used DECT phones for years, and never had a problem. My router and the DECT base unit are only about 1m apart.
I could believe it may vary according to make/models of the router and phone, but it is certainly possible to have DECT phones without any problems.

DECT is no inherent issue, but noisy PSU may cause issues for some, and older cordless phones may have shared the same frequency bands as old wi-fi

I have a Panasonic KX-TGC222E DECT phone and base 800mm from the OR ADSL/VDSL Faceplate, 60mm right next from the PlusNet Technicolor TG582n router and 900mm from my desktop and I�m on ADSL+2 and my download speed has been the same for 10 years or more at a steady 16+Mbps, first with O2 and now with PlusNet Unlimited Broadband so the DECT phones do not seem to have a detrimental effect on the internet speed.

Thanks, all of you, for your helpful inputs. The concensus among you seems to be that modern DECTs present no problem in this regard. Looks like he's got nothing to worry about, then.

These days there are some very competitively priced FTTC/VDSL services which your relative might want to consider. My Gigaset N300 DECT base station is about as close to my VDSL Wifi router and telephone wiring as is possible. I have not noticed any problems.

In the UK, DECT uses around 1.8 GHz as the transmission frequency. This is outside the range of ADSL, VDSL or even G.Fast. Also it does NOT interfere with WiFi on 2.4 GHz, so there should be no issue.

Just to add to the confusion, my Fritz 7390 combines adsl/vdsl modem and router with a DECT base station all in one unit. seems to work very well and provides a neat solution if you are looking for minimal clutter.

In reply to a post by warweezil:

Just to add to the confusion, my Fritz 7390 combines adsl/vdsl modem and router with a DECT base station all in one unit. seems to work very well and provides a neat solution if you are looking for minimal clutter.

Interesting product! What do you do for telephone DECT hand sets? Can the integrated DECT base station work with the incoming phone line or is it just VOIP?

IIRC It can link with other handsets, but I found a couple of Fritz branded ones (Model MT-F) on fleabay and have them installed. They have a couple of nice touches in the configuration menus like larger text on the handset displays, the ability to use the handset as a nightlight etc, they can recieve email and rss feeds too if thats your thing. ISTR you can set up multiple answering machines too. Very versatile with lots of little touches you can configure. I got the 7390 for the user interface, the phones were just the icing on the cake when I found them

You can probably find clearer information if you dig around.