atcomsystems.ca/forum Forums General General Telephone & Systems Information New Here and a Question or Two

Hello everyone!

I've been lurking the past few days, and decided to sign up. Figured I'd post a quick intro, then get into some of the questions.

I'm a network engineer/admin as part of my job. I primarily work with Windows-based OS'es, but occasionally deal with Linux as well. Love to play at the network level with everything, but in my current path, I'm rather limited as to what I can do, as it's a small environment (I'm the IT department at the location I'm at, and a major player when I'm down at the plant).

I recently received my grandfathers old butt set from his days working for Michigan Bell. I know it works as I took an old phone cable, stripped off one end, plugged it into the jack, then attached the butt set to it. Wasn't surprised that it worked, was very fascinated to find that rotary still works around here.

Anyway, with all that said, I've got some questions:

- What are the different types of blocks being used? What differentiates them? Why use one versus the other?

- I'm fascinated with installations and troubleshooting/testing. Is there a good book (I hate reading online for anything extensive) that covers basics when it comes to both sides of the demarc point? I'm as interested as what the telco does running lines to the demarc and their testing, as well as what an installer does with phone systems and their testing. Not sure I'm necessarily looking at a career change here, but you never know.

- I've seen references to the splitting of pairs, and how an installer had taken down an entire floor in an office building by using what he thought were inactive pairs (or something like that). I guess the question here is, what is the splitting of pairs/how does it work?

I've been fascinated with communications for as long as I can remember. Digital, analog, wireless, wired, etc. Telephones I guess fascinate me more than I thought, I just never realized it till I received my grandfather's butt set.

Just wanted to say thanks in advance for any answers. I'm still reading constantly here, so I may have answered some of my questions in the reading, but I still appreciate everything.

Thanks!
Scott

This one should be in General. Moving.

-Hal

I know we've had questions before about books for basic telephony, but I can't seem to find them. I'm sure someone will be along soon to tell you where to find them.

Lee's ABCs of the Telephone Series had a lot of the basics, but I don't think it's still being published. There are copies of some of the series available on Amazon.

There are a lot of different kind of blocks out there. The most common are:

66 (Have been used for voice for many years. Easy to work with and reliable)
110 (Standard for data)
Krone (Popular with carriers [Verizon, AT&T etc])
Bix (Standard in Canada)

Wirewrap blocks are common in Central Offices and with carrier equipment

For more information try Wikipedia and then come back and ask some more questions.

Solder terminal blocks were standard in the COs, but are not used much anymore

There were numerous others over the years that are not used much (if at all) anymore (Telzon, 3M etc.)

As far as splitting pairs - That shouldn't effect more then one individual line - UNLESS - the line is part of a carrier feed in which case, yes, you certainly could take down a load of circuits.

Sam

Bill, I think it was in a private forum like "Installers".

Scott, to the BB. Hope you hang around and you can help us with the computer network stuff.

As far as learning, a company by the name of "ABC" had a series on just about anything telephony. They used to advertise in a trade magazine called "Telephony".

As far as blocks, which usage are you interested in? Different usage...different blocks.

Rotary works no matter what in a real telephone office. That is considered basic service. You pay extra for tone dialing. This is due to state tariffs. All the other "telephone companies" such as Time Warner, etc., may not work due to their type of service.

Just keep your sense of humor about you, smile, and hold on the ride of your life.....hope you enjoy the BB.

Thanks for the welcome and the responses!

At this point I'm interested in learning anything and everything. So I'll definitely be around be sticking around!

And I've already learned quite a bit today too.. I did not realize that when it comes to rotary. That's very cool, and explains why I had no issues with the call from my grandfathers old butt set.

Thanks!
Scott

[QUOTE]Originally posted by Silversam:
Wirewrap blocks are common in Central Offices and with carrier equipment


Wow, I did not know that. I haven’t been in a CO in quite awhile but that surprises me. It’s been about 15 years since I did any wirewrap, we ripped the last of it out about 5 years ago.

We still have wirewrap in the main switch room on campus. I was pretty surprised when I saw it.

We still have customers in DC with solder frames. Rest assured, they are out there especially in larger cities. One hospital that we service has a total of 2,850 incoming pairs terminated on solder lugs. They have in excess of 10,000 house pairs terminated on the back side of the frame the same way. The place isn't that old either.

Wire wrap is much more commonplace these days for "critical" circuits at the customer-premises. It is also very common in central offices to save space on distribution frames. This method is much more tolerant than traditional IDC (insulation displacement connector) technology which is more commonly referred to as 66, 110, Krone or BIX. Wrapped or soldered connections are permanent: They don't come loose until you want them to.

With IDC, if you yank on a jumper wire that is 100 feet long, you might damage the termination at the far end. With wire wrap or solder frames, you'll probably damage your fingers more than the connection.

IDC terminations were designed for installation speed. Wire wrap and solder terminals were designed for longevity.

We still have customers in DC with solder frames

Ed, I hope you don't have any left handed techs working on those frames.

And for the wire wrap remember, 5 wrap minimum and no shiners

Already learning a lot! I love this place..

Okay, a couple of more questions.

- On the butt set I have, there's two plastic tubes that run up and down the length of the cord. I've seen it on other sets as well. What are they for?

- Related to the butt sets, when I've been looking at them online, I see some that aren't supposed to interfere with DSL. If I remember reading right, it has something to do with voltages. Could someone explain further? What happens if it were to connect a butt set to a line with DSL on it? Does it just drop the DSL connection? Is there potential for equipment damage? What about connecting it to a data circuit, such as a 2 wire T-1?

I printed off a bunch of Wikipedia articles yesterday, but haven't had a chance to go through them yet. So I'm sure once I do, I'll have even more questions.

Thanks again!
Scott

If you mean the plastic tubes on the cords, I believe they're just there to keep the cords from tangling. You slide them down and that straightens the cords out.

An off-hook Butt set is like a telephone. If you hook a new telephone up to a line that has DSL and don't put a filter on it, you will interfere with the DSL signal (reduce the speed). You won't damage the equipment but you won't help the circuit any.

If you connect a butt set to one side of a 4 wire T-1 line and you will knock down the line. A 2 Wire T-1 line is a form of DSL and I imagine you will interfere with the speed of the circuit.

Keep asking. That's why we're here.

Sam

It affects the operation of a data circuit because by placing the set on to the line you're affecting the impedance of the line itself. These sets were designed for testing basic phone lines (known as a POTS line for 'plain old telephone service'). When you connect your set on to the line with it on-hook you're bridging on to the line. The DC resistance is high because a capacitor inside blocks DC from passing while the device is on-hook. AC will still pass through the capacitor and activate the ringing circuit of the telephone if it's at the right voltage (90V at 20 Hz)... The AC going through the capacitor is fine because phones operate on -48V DC for what's known as 'talk battery'. When somebody picks up the phone, contacts inside the phone (or butt-set) connect the circuitry inside to the line and you can talk on it, make a call, whatever...the voltage at that point will then drop to about -10V or whatever needs to be there to provide approximately 21 mA of current. Once the line is back on-hook, the voltage will go back to -48V since again the DC will be blocked by the capacitor.

That's a rather long explanation but as an engineer I imagined you'd appreciate it.

Anyway...that's all good and fine for voice, but with data there is no on-hook or off-hook...you have data streaming continuously and by nature it's AC and therefore will pass through that capacitor in the butt-set's ringing circuit just fine. If you put a butt-set on prior to the DSL filter, like Sam said, it will hurt the speeds and maybe knock it down a bit but DSL is a very 'hearty' service (for lack of a better word) and will overcome a lot of changes and survive. A T1, however, is a bit different and is a lot more sensitive to the impedance depending upon what type of delivery method is being used to bring it to the site. Usually there is 100 ohms of impedance on a T1 line and it is not designed to operate with things bridged on to the line...

Hooray for wire wrap "They don't come loose until you want them to." I still have my wire wrap gun and wire stripper tools.

I did some wire wrapping just today... We still use them in our COs on DSX-1, QCP, and DDP panels.

I have used solder ones as well but those are pretty rare these days.

My electrical knowledge is a little rusty, but I remember enough that that made sense. Thanks Matt!