atcomsystems.ca/forum Forums Telephone Services Cabling Telephones Systems Wiring JK Cable Question

Going old school with this question.

I, vaguely, remember a topic about JK cable.

Part of the discussion, if my memory is correct, mentioned that the familiar green, red, black and yellow cable was used for Princess phones. Red/green for audio/signaling/dialing while the black/yellow was the power pair connected to the external transformer.

Was JK intended to be used to wire only a single telephone line, or, was it produced to be able to support two lines from the get-go?

Due to the lack of twisting, crosstalk would be an issue for long runs.

Bingo! I was looking in the Cabling forum as opposed to the 1A2.

Danka Professor!

my earliest recollection is that the yellow was used most of the time between protector and ts to provide independent ground for party line ringing and party identification for billing purposes. jk could not accommodate the wire needs for the five conductor early trimline or princess models.

Was the cable only three conductors? If it had four, what was the black used for?

The old original station wire was 20 gauge 3 wire, it replaced the 3 wire braded wire which was originally cloth cover, than rubber, no jacket.

I've seen the three wire braded cable. I think that I might have a few small sections stashed away in the basement. Based upon the discussions, it seems that JK wasn't intended to support two POTS lines despite having four conductors.

A while back, I had combined my church's two voice lines onto a single JK cable which ran about a total of 10 linear feet between the Verizon H-202 cabinet and the 66 block I had installed as a demarc.

After the church service ended today & the 4 or 5 people left the building, I pulled a hank of JK out of my stock and moved the second voice line over to it. I suppose such a short run between the cabinet and the 66 block wouldn't pose a crosstalk issue, but, I figured that I would separate the lines again.

Because the wires are not twisted pairs it was never intended to support two POTS lines. Problem is crosstalk. That's not to say that it was never used for two lines, you can get away with it but the longer the cable the better the possibility you can have crosstalk problems. (And don't ask me how long because I have no idea.) I remember that you will hear the ringing from one line while the other is in use.

-Hal

With all of the other POTS cables being CAT3, (and not experiencing any crosstalk), I figured that I might as well separate the two lines.

Now this brings up an interesting point. The daycare that leases space from us is has two POTS lines (1 voice & 1 fax) and two DSL feeds.

It seems that New England Telephone ran both phone lines from the telephone closet to the other side of the building via one JK and the other cable just has the voice line.

The distance between the phone closet (aka my office) and the daycare's areas is, roughly, 70' to 80'. I'm surprised that, after 30+ years, that nobody from the daycare hasn't complained about fax/data bleeding onto the voice line.

Then again, they had wall phone plugged in without a DSL filter for many years. A few months ago, I grabbed an unused filter and connected it to the phone for them on a day when they were closed.

How the heck did the DSL work? The ringer would have killed it.

-Hal

The particular phone is used for emergency outbound calls, so, I don't know if the ringer is turned off.

The daycare's director says that the phone hasn't impacted their DSL service, but, I can't confirm or deny this. My way of thinking is, if you subscribe to DSL, filter everything except the modem, so, I dug out one that had been lying around in my storage area, plugged it in one day a while back when the daycare was closed due to the pandemic and checked to make sure that the dial tone was clean & that I could call out.

No kidding. Every call in should have killed that DSL service. Not to mention the DSL "noise" they surely had to be hearing on every call.
Unless there is a splitter in the NID/Demarc that has a filter built into it. That is what we do on the majority of installs. Eliminates alot of house wiring issues and customers removing filters. Just requires someone to visit when a customer wants to move the modem to a different location.

This particular phone is only used for emergencies. The regular phones have the required filters. But with my adding the filter, all phones now have them.

DSL is a lot more resilient than people think. It really only requires half of a pair to function. It uses the copper as more of an "antenna" to ride along than an actual loop. I've seen this on many occasions. Of course, speed is incredibly inconsistent and tough to troubleshoot, but it does work. Where I am, CenturyLink's only real option is DSL, although they do sell a good amount of bonded DSL for commercial accounts that works surprisingly well. I've seen some pretty shady "installations" in old mills and factories involving hundreds of feet of junk wire that have supported it just fine. Yes, I walked away scratching my head too. JK wire is perfect for DSL, in fact I believe that the entire concept of DSL service in general was designed around adapting to CAT Zero wiring on the premises.

If it can survive over thousands of feet of aerial 'C' wire, or century-old pulp cable, a few feet of JK is a walk in the park. I stocked up on ivory JK wire before it went out of style and still use it pretty frequently on residential work. We encounter a lot of three-conductor JK wire that was originally installed back in the 60s and 70s by Carolina Telephone, in fact my apartment is fed by one, but I don't remember any Bell companies using it in my lifetime.

I can attest to DSL working on terrible wiring. When the bar was having all those issues, it would still work more or less. All that time the final problem ended up being an undocumented bridge tap in the manhole behind the building. There was around 1000' of unused bridge tap going off somewhere, and while it didn't work right, it did work. What really amazes me, is what the possible throughput is once everything is right. We have bonded VDSL. We pay for 40/10 and get every bit of it. The last time the tech was there, his max theoretical throughput came out to around 48 Mbps PER CIRCUIT. So darned near 100 megs combined. This is on about 1800' of pulp cable from the CO to our BET. Simply amazing.

Imagine if all of the bridge taps were eliminated. I think that would allow for faster DSL service to be offered.

Yup. Didn't somebody here talk about DSL still working even though the ring was open someplace?

-Hal

Apparently, according to the tech I was working with, ADSL can tolerate some monkey business going on with the loop, but VDSL, especially VDSL2+ really needs a good, clean loop with no taps.

and if it is bonded, then the cable length has to be within 5% (?) of each other.

From what I've seen, just about all of Consolidated's DSL installs in my area are bonded. It's a mixed bag of ADSL and VDSL, but even my friend's store is bonded, even though it's only 15/2 ADSL. He's less than 1000' from a hut.