Is CAT 6 cable okay as a telephone line?

You can, it will work just fine, but telephone wire is much cheaper and fits the IDC accessories correctly.

I'm not sure if the BT/Openreach/KCOM/whatever rules say, but physically it should be fine. Structured wiring was originally designed to support POTS as well as data and the usual RJ45 sockets are designed to accept US style phone plugs - and I doubt that the CAT3/4/5/6 improvements have made things worse for phone signals. Certainly my phone line at home wanders over a UTP CAT6 structured wiring system without any apparent problems (using appropriate RJ45-UK phone socket adaptors).

   - Andy..

It’s for a lift, I started the job in May when I went on a nice sunny Saturday to run a new circuit to supply a battery charger for the lift, an electric garage door, lights and a double socket for charging mobility scooters.

The lift is in an attached garage and goes up onto a balcony above to gain access to a flat, now a different lift is going to be installed to what was originally specified and this lift needs a dedicated circuit and a phone line.

So I have to go back to install these, but I have it in mind the copper phone network is going to be turned off in a couple of years time, also the cables have to be run externally, so using external grade CAT6 cable seems far more sensible than a bit of standard phone cable as it will be internet ready. The circuit I have already installed will still supply the electric garage door, lights and the double socket for charging the mobility scooters.

This time around I will probably be up an extension ladder in the rain getting soaking wet, rather than putting sun screen on as I did in May.

I think it’s probably about seven years since I last ran an actual straightforward telephone extension, in another couple of years there won’t be a copper phone network to connect them to, we may not have ours in a few weeks from now.

There are loads of things that will need to be replaced that are currently connected to telephone lines, like emergency call pendants in homes without internet.

in another couple of years there won’t be a copper phone network to connect them to

I was rather hoping that box on the customer's end of the fibre or whatever will have the ability to plug-in a traditional phone - effectively emulating the old exchange line.

   - Andy.

I've been able to plug my "traditional" master phone c/w answerphone directly into the router, and the three other slave phones still work with that.

BT rather helpfully gave me an internet voice phone to boot which works independently and which means whilst you're fielding one landline call another call can come in. This has the benefit that whilst Mrs G is engaged on one of her interminable social calls I can still make calls out.

BT used to do that years ago, under the name BT Broadband Talk.  They killed the service when they realised it wasn't making them any money - the service was cheaper for calls than a normal land line.

I said above the last time I installed a dedicated phone line was around seven years ago, it was actually 2016 just after Sky Q was introduced.

Some builders I was working for managed, without much effort, to destroy the existing phone line to the customers study, so I replaced it and thinking about it I did use Cat 6, but after I finished a BT guy came and rejigged the phone line to try and bump up the internet speed for the customers new Sky Q set up from around 3 Mbps and had a fiddle with what I had done along with the alarm phone line.

A lot of the customers don’t have a landline phone anymore and I certainly thought running phone lines was a thing the past.

It don`t seem two minutes ago we were barred from doing any work that involved BT phone lines or part thereof. I remember I was fitting one of the old autodiallers for a burglar alarm system and a BT engineer turned up to work on the phone line. Phones were connected to the line by a junction box back then and he was fitting a "new fangled" master socket to allow phones to be "plugged in" . WOW. 

I thought I`d advise him that leaving the junction box thereabouts make make life easier because within a few days I would be connecting said dialler. Well he right uppity about that "YOU WILL NOT TOUCH THIS WIRING OR ADD ANYTHING ON THIS LINE ONLY US CAN DO THAT< OTHERWISE IT IS ILEGAL!" he quoted sternly.

I explained the dialler was type approved and I had sent the card in requesting permission to connect and requesting the appropriate JB but he were having none of it.

A few days later I was on site again waiting to connect the dialler as arranged and guess who turned up to do the BT bit? Yes , same chap, strange he never mentioned our previous conversation Ha Ha Ha. Priceless.

A few years later I arranged for a new telephone line in a small factory for a communicator. Engineer turned up on site insisting it could only be within a few yards of the existing "Or they will charge you for it". I said "Yes it has been paid for and they have agreed to put it here!" He were not at all pleased it was a fair long run. As he was packing up he left a brand new phone handset. 

I informed him the handset was not required just the line for our equipment "YOU MUST HAVE A PHONE ON RENTAL WITH A NEW LINE!" so I rang Telecom Sales " Is it a requirement to have the phone too?" . NO. I handed him the phone and said "Telecom Sales would like to speak to you!" . After talking to them and protesting what was always rules he left with that phone. 

How times have changed

Back in the 80’s I was working on new housing sites as a carpenter, firms like Beazer used to sell the house purchasers “Telephone extension wiring” and if the customers paid the phone extension cables would be installed, but no sockets were fitted and the cables were not terminated, they were just left hanging out of the wall, then it was up to the customers to get them finished off.

Beazer had had arguments with both the customers and electricians when the extensions had been fully installed, because if there was a fault the customers would phone BTwho would turn up and say the fault was in the extension, so nothing to do with them, then slap sixty quid onto the customers next bill as a call out fee.

There we’re then arguments about who should pay the sixty quid, so Beazer decided the cables should just be left hanging out of the wall.

Then they did the same again with burglar alarm wiring.

Many firms still do similar things, such as installing the wiring and bell push for a door bell, but not the actual bell itself as that is an optional extra.

Fitting immersion heaters, but not connecting them is another example of modern day silliness that new home purchasers experience.