If you suspect a phone handset you should test to eliminate that by using something like this.

(It's also handy to have something like that as you would still have a working phone in the event of a power cut)

Edited by jelv (Wed 16-Jan-19 00:08:15)

@john,

Thanks John, will give that a try, although we have had a DECT phone plugged in for years with no effect on speeds AFAIK.

@jelv,

Funny you should suggest that, as i bought one from eBay last night.




Over a 24 hour period, the errors are now at...


CRC: 119113
FECS: 1884262
ES: 5405

Just getting a bit concerned DLM might rear its head soon.

Edited by Alucidnation (Wed 16-Jan-19 06:52:08)

As an update, plugged in another filter so that the phone was double filtered and this seemed to make no difference at all.

After about an hour it was racking up errors so i unplugged the new phone from the phone socket and left it all day and checking the stats when i got home around 4, there were barely any errors registered at all.

Let us know if DLM does take any action as with 5000+ ES in 24 hours it is very likely the line could have interleaving enabled.

It's a shame the double filtering has no effect as this has worked in the past.

Interleaving applied last night.

I obviously wasn't quick enough with unplugging the phone.

Limit is either 1440 or 2880 ES in 24 hours.
Which 1 depends on the ISP.
Safe to say you smashed that.

The line now needs stability and multiple concurrent days with low ES before it will return to fastpath.
If fastpath is important to you (eg gaming) then you should put the phone testing on hold.

Your old handset had 799 ES in over 24 hours which is perfectly fine for fastpath. Was that also a DECT phone?

Yes it was, around 5-6 years old.

Since interleaving was applied this morning around 3am, i have no ES errors at all for the last 10 hours.

Actual sync speed has dropped from 58ish to 52, with a now obtainable of 60.

Still no phone plugged in.

After leaving phone unplugged for a while, i had no es errors and a few FECS errors.

I plugged the standard 'wired' phone in for a couple of hours and also, no ES errors.


With that i plugged back in the new DECT phone just to have a quick look and so far, still no ES errors however FECS errors have shot through the roof!

I will unplug the new phone later, but will interleaving suppress any ES errors that would be likely to occur?

Do FECS errors get monitored by DLM?

Thanks guys.

Edited by Alucidnation (Fri 18-Jan-19 17:08:16)

Yes, interleaving/INP is set to use FEC (Forward Error Correction).
Those FEC's are errors that have been corrected, preventing ES.

In my experience DLM won't return the line to fastpath with excessive numbers of FEC.

There are particular brands of DECT phones that play well with FTTC and others that don't. It's not my area, I don't have a landline connected at all.
No idea if you are able to return the new DECT phone you bought but the line won't hold fastpath with it, if that's important to you.

Low Interleaving adds 8ms delay and knocks (very roughly) 10% off the sync compared to fastpath.

If you don't mind 8ms latency and a few Mb off the sync then interleaving can be a bit more stable with less packet loss.

What's your sync now, 53-54Mb?

Edited by j0hn83 (Sat 19-Jan-19 02:27:01)

Hi John,

Thanks for the detailed explanation.

Yes, at the moment i am syncing at around 52 with an attainable of around 60.

I have just unplugged the DECT phone after 10 hours and FECS have risen to 338578860, whilst ES are at 49, and CRC 50.

The only reason for wanting a portable phone, is that the phone line enters the house from underground in the lounge and it's position is tricky to have comfortable phone conversations in it's current location.

Yes, fast path is reasonably important as the kids do a fair bit of gaming.

Thanks again.

Edited by Alucidnation (Sat 19-Jan-19 07:18:01)