Dacs lines

So our remaining landline (with talk talk - was po/shell/octapus brought and sold) has been ported over to voip (finally) and as some of you already know its a dacs'd line. When the number was ported, the line changed number and was still active (17070 works) but you can't call the new number. Is this normal or should i inform talk talk.

Same with my old landline when I ported it to VoIP about 3 years ago. There was a new number on the copper pair, but you couldn't call it (or call out on it). Don't know if it was DACS, but from the quality I doubt it. The was a WLR line via Zen.

my non dacs'd line when i did the voip transfer last year just went dead but that had fttc on it.

If it's a DACS line then you can't possibly be doing broadband over it, so you should just treat it as no longer existing (just make sure Talktalk aren't billing you any more).

I expect all DACS equipment will be decommissioned as part of PSTN switchoff, which was due for Dec 2025 but pushed back to Jan 2027.

That's a TalkTalk thing rather than a DACS or porting thing. I wouldn't worry about it. TalkTalk used to have the same different number issue when they were in pre-provide state.

Edited by FibreBubble (Fri 30-Aug-24 10:02:11)

I doubt there are many DACS left now. I did a lot of work on recovering DACS on an exchange by exchange basis about 10 years ago.

It’s extremely unlikely that the line was DACS ( digital access carrier system ) , even in the mid 1990’s DACS was problematic with 56Kbs modems , let alone broadband, and TT being a LLU/MPF provider, DACS was never compatible….DACS was ‘invisible’ from the end users point of view, so its removal would not be noticeable, the end user not notified of its removal, there was no need for that level of customer engagement, DACS was only ever a telephony solution to a copper pair shortage, broadband effectively killed off DACS decades ago .

As fas as a stopped line , retrieving a number ( via 17070 ) that is unrelated to the customer (, and doesn’t accept incoming calls ) , is pretty normal on a stopped line , to allow a port of the original number the ‘line’ is stopped and renumbered, the idea being that should service be required over it again ( fairly academic with PSTN switch off ) the line is ‘start/renumbered’ .

The line may quickly go ‘dead’ , if a cease order is raised , however these are ‘BT’ protocols , if the line were TT LLU , they may do something similar.

Edited by Iniltous (Fri 30-Aug-24 10:08:30)

In reply to a post by Taras:

When the number was ported, the line changed number and was still active (17070 works) but you can't call the new number. Is this normal or should i inform talk talk.

Probably means your line is wired to a TalkTalk DSLAM / MSAN at the exchange, rather than an Oprenreach/BTwholesale DSLAM. Ignore it.

Multiple engineers over the years have stated it was dacs. There was an engineer as late as june/july (can't remember when now) who didn't believe me when there was a fault on the line. He came back saying "yep the line is dac'd "

talk talk have taken over everything that was post office (non llu) that went to shell energy .. so i doubt talk talk moved non vdsl lines over to the llu side

For a TT LLU ‘line’ to be on DACS it would have to be that TT took over service from someone else , and that service was already provided via DACS , TT themselves would have to only be providing a voice only service , and the sharing partner on the DACS would also have to be a voice only service ( that’s a extremely unlikely scenario )

if someone was on DACS as a telephone only customer and their DACS partner (also a telephone only customer ) was ceased or they ordered broadband in both situations the partner is either disconnected or moved onto their own copper pair ( so broadband will work ) so there is no longer any need for DACS to exist on the remaining telephone only customer, , and it should be removed , , it’s pointless to leave a single worker on a DACS .

I will concede that it’s possible a single telephone only DACS customer may be left in service on DACS , however the very first fault report on that DACS line , it’s inconceivable that the tech wouldn’t convert that single DACS to a DEL ( direct exchange line ) .

AFAIR , DACS was a voice band product , it’s input needing to be the range 300hz-3.4khz , it provided ( 2x128Kb voice channels independently of each other and never was compatible with ADSL .

There are still telephone only customers and perhaps they were two at some point working on the same DACS , but today the chances of 2 telephone only customers at the same DP ( where the DACS remote unit is located ) is slim , and keeping a single user on DACS is pointless.

FWIW , every exchange I’ve visited in the last 10 years , any DACS shelf I’ve seen , although in many instances still powered up , are invariably showing ‘alarms’ showing the exchange kit has no remote units connected to it .

Edited by Iniltous (Fri 30-Aug-24 17:14:59)

In reply to a post by Iniltous:

For a TT LLU ‘line’ to be on DACS it would have to be that TT took over service from someone else , and that service was already provided via DACS , TT themselves would have to only be providing a voice only service , and the sharing partner on the DACS would also have to be a voice only service ( that’s a extremely unlikely scenario )

Was originally with BT. Its a 30 year plus old line and number. The number, got moved from, bt to the post office, then shell energy brought out the home phone and broadband unit from the PO. After being bundled over to shell energy, octapus energy brought the unit from shell, and now TT has those customers.

In reply to a post by Iniltous:

if someone was on DACS as a telephone only customer and their DACS partner (also a telephone only customer ) was ceased or they ordered broadband in both situations the partner is either disconnected or moved onto their own copper pair ( so broadband will work ) so there is no longer any need for DACS to exist on the remaining telephone only customer, , and it should be removed , , it’s pointless to leave a single worker on a DACS .

yes i totally agree.

In reply to a post by Iniltous:

I will concede that it’s possible a single telephone only DACS customer may be left in service on DACS , however the very first fault report on that DACS line , it’s inconceivable that the tech wouldn’t convert that single DACS to a DEL ( direct exchange line ) .

Again i agree, i even asked for it to happen this year, but the other line to the property is now dead and the engineer didn't know how to handle that so he just fixed the issue, and it [the issue] reappeared 2 weeks later.

is a Del line a normal line ?

In reply to a post by Iniltous:

AFAIR , DACS was a voice band product , it’s input needing to be the range 300hz-3.4khz , it provided ( 2x128Kb voice channels independently of each other and never was compatible with ADSL .

Ahh thats how it worked

In reply to a post by Iniltous:

There are still telephone only customers and perhaps they were two at some point working on the same DACS , but today the chances of 2 telephone only customers at the same DP ( where the DACS remote unit is located ) is slim , and keeping a single user on DACS is pointless.

FWIW , every exchange I’ve visited in the last 10 years , any DACS shelf I’ve seen , although in many instances still powered up , are invariably showing ‘alarms’ showing the exchange kit has no remote units connected to it .

I don't know if we were where the only one on the dacs unit, but now the number has been voip'd the info is just for fun and interest and i do appriecate you and others responding ❤

In reply to a post by jchamier:

In reply to a post by Taras:

When the number was ported, the line changed number and was still active (17070 works) but you can't call the new number. Is this normal or should i inform talk talk.

Probably means your line is wired to a TalkTalk DSLAM / MSAN at the exchange, rather than an Oprenreach/BTwholesale DSLAM. Ignore it.

i don't know if Talk Talk did move it from OR kit when they moved the accounts from shell energy. The move has taken some time for them do various accounts and you aren't gonna get that info from CS reps

In reply to a post by Taras:

i don't know if Talk Talk did move it from OR kit when they moved the accounts from shell energy. The move has taken some time for them do various accounts and you aren't gonna get that info from CS reps

I saw the Shell energy -> Octopus -> TalkTalk transfer, as Octopus bought the Shell Energy business (over 1.2million energy customers) but didn't want Shell's broadband business, no idea how many of you there were.

As a discount operation TalkTalk would have looked for the lowest cost way to move everyone across, and as one of the operators of their own hardware in Exchanges for ADSL and voice, they could have switched the voice over to TalkTalk exchange hardware.

This would also explain the difference in experience from the stopped line (after VoIP migration) between TalkTalk hardware and BT/Openreach hardware.

It is perfectly normal for a line which has been stopped to become some random other number … the DN which worked on it has been ported out, this new one is just a sort of ‘place marker’.
I expect the original DN was always provided by BTw voice, it used to be that LLU services were not provided via DACS.

Niche ( and useless ) info … if your old line was the B1 (bearer line) then if the 49v DC stopped from the exchange , then eventually the second line (B2) would pack up too … but often not for several months.

I will concede that it’s possible a single telephone only DACS customer may be left in service on DACS , however the very first fault report on that DACS line , it’s inconceivable that the tech wouldn’t convert that single DACS to a DEL

Really ? Inconceivable? The push for prod. Why go to the exchange to deshare the exchange equipment if you’ve an easy clear elsewhere ? Let’s factor in that remote tests of a DACS line were a lot more ‘forgiving’ a deshared line much less so. Climb a pole just to remove the RU …… I’d say it was completely conceivable.

For a TT LLU ‘line’ to be on DACS it would have to be that TT took over service from someone else , and that service was already provided via DACS , TT themselves would have to only be providing a voice only service , and the sharing partner on the DACS would also have to be a voice only service ( that’s a extremely unlikely scenario )

Just leaving it as how it was as the customer only required voice service …. the cheapest option … and easiest too.

There are still telephone only customers and perhaps they were two at some point working on the same DACS , but today the chances of 2 telephone only customers at the same DP ( where the DACS remote unit is located ) is slim , and keeping a single user on DACS is pointless

There are still plenty of telephone only lines. The remote unit didn’t have to sited at the DP, UG before the DP, or splitting after were all equally possible. One line might have carried on a long way , down, say, multiple spans after the DP … for instance.

As before, leaving a single worker on a DACS is the quick/easy/cheap option … and there’s the truth of it.

They were fitted when a second line for dial up became all the rage, many failing to notice the service gave 24kbps rather than 52kbps …

Quick/easy/cheap ….

Edited by Zarjaz (Sat 31-Aug-24 15:57:22)

I’m aware that DACS could be fitted at the cabinet , in fact I know of an area ( going back nearly 30 years ) , where senior management veto’d a 800 pair to a new cabinet for that estate, the ‘logic’ being as the area was bound to get ‘cable’ , so the 600+ housing estate got a much smaller cable than the policy of 1pair per tenancy dictated, unfortunately the cable company arrived many years after the estate was completed and not as quickly as the senior management anticipated , so a huge number of those properties were DACS , ( literally dozens of remote units in the cab base as well as in joint boxes ) so in those cases the DACS partners were probably served from different DP’s , ( DACS remotes can be in UG and OH varieties but this was a new estate and entirely UG ) ) , but my ‘experience’ was more in the planning and construction implementation field than actually fitting the things in the field , so policy may well have been dismissed in the pursuit of ‘prod’ …

Although never directly in ‘the field’ , I knew many that were , perhaps they were conscientious ( or claimed to be ) and would not leave a single user DACS on a line with a fault report, but again policy 30 years ago was to leave it as a PGD ( pair gain device ) , but when internet access became more than a niche activity the policy changed as they were then something of a liability.

Different areas may well have different policies, but that’s all pretty historic, I suspect the number of working DACS , single or duel working in 2024 must be an incredibly small number , it was my understanding that the entire DACS estate was retired, but maybe not .

Edited by Iniltous (Sat 31-Aug-24 17:06:59)

No, not retired, yet. The last time I worked on one was at the start of the year.