atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Troubleshooting help, please?

Arthur -

What sort of "thing" did the home runs terminate on? I'd like to home run all of mine, but don't see how to do it. And 12,000? All I can imagine is a "66 block" (I'm sure it has another name, whatever it is)where every row is common, but the size is about 10' x 10'.

Still so much magic to understand.

- Matt

Matt -

We generally terminated on 66B4-25 blocks that gave you 5 appearances for each line. If we had a situation that called for more terminations we would sometimes put the blocks with the feed pins touching, run the feeder cable up the middle and loop it on one block and punch it down on the other one. This gave us 10 terminations. For situations that required more appearances then 10 we would just duplicate this scenario.

I did a job once that had over 70 K-30 sets. All picked up the same 20+ lines. The frame room was huge. 75 pair for each of the sets. It was a blown out ITT K-76A system - I think it offered 54 Intercom extensions, 3 or 4 channels of Intercom and 24 CO pick ups. We maxed it out and then some. Had to put lamp extenders on.

The job started with about 40 stations and just grew. They tried to sell the owner a PBX at one point, but he was having none of it. I showed up there once and someone had run out of space in the frame room and had commandeered the coat closet next door. He punched a hole in the sheetrock and ran the cross connects through the hole in the wall to the blocks in the coat closet.

I was appalled.

A big job like a hospital is different from a small key system. There is key equipment, but it backs up a PBX. Usually there are no more then 3 or 4 stations picking up the same line (Boss, assistant, secretary and covering secretary). There were exceptions of course.

Sam

This is where the colored backboards all started..

Matt:

The hospital was Mt. Sinai in Manhattan. It has one main BIG building, taking up a half city block, with a height of 27 floors above grade, and three levels below grade. The other buildings are older and generally are 6 to 10 stories, but there are many of them.

The big building was cabled by electrical contractors, under the supervision of our lead man, who had designed the entire telephone layout. He was the lead man for many years and set the rules.

Every floor was wired identically. The layout of every main room and all of the satellite closets on every floor was uniform, with only minor differences due to the type of activity that took place on the floor.

On each floor, there was a main tel closet and three satellite closets. The main closet served as a fourth satellite, as well as its function as an equipment room. All telephone cables ran home to the 4 satellites, and were headed up on 66M-50 blocks.

The main room on each floor (the rooms were in the same "stack", so all cabling ran up a chase from the sub-basement to the top floor) was lined with chipboard on all walls, providing about 250 square feet of mounting area per main room, and the satellites had one 4 x 8 sheet of board each.

The main room on every floor had a floor-to-ceiling 23" equipment rack, which held anywhere from three to ten 584 panels. These are 1A2 common equipment that each hold 13, 400-type line cards. A large power unit or two was used to power the rack. Western Electric made a power cable that had 6 pairs of cotton-covered 18 gauge wire, covered in light olive gray (color suffix -49) plastic sheath. That was used to interconnect the panels.

The first panel in each rack had an interrupter, and subsequent panels had a plug-in relay unit in place of the interrupter, which was driven by the main interrupter, so that the flashing and winking lamps and the ringers of all lines on all phones would operate at the same cadence. If the number of lamps per circuit exceeded the design limit, solid-state lamp extenders were installed with a separate power unit dedicated for them.

The output cables of each panel were punched down on three 66B25 blocks each, giving 5 output pins for cross-connections. As an example, a room with eight panels would have 24 66B25 blocks just for the source of the features for that floor. The cross-connections sent the "features" to 66M-50 blocks which were the "source" end of individual 25-pair cables, each going to an individual 6- or 10-button phone. In the event that more than 5 phones needed the same features, we used "multiple" blocks, which could be wired using the loop-through method, providing as many multiples as needed, either in the main room, or at the other 3 satellite closets at the other quadrants of each floor. If more feature outputs were needed, more multiple blocks were added. There were NO bridging clips allowed, unless they were used for temporary service, while multiples were being installed.

Intercoms were the Teltone R-10 and R-19 units, each of which had its own 25-pair cable feed to a modified 66B-50 block.

A common audible lead from each 400D KTU fed a wall of diode matrix blocks. Strict physical layout rules and cross-connection color codes ensured that a repairman could walk into any room and find what he was looking for immediately. CA leads were red. Ground was black, fed from a large multiple 66 block. Every satellite had a ground multiple block, so that lamp grounds could be kept to a minimum resistance. Green was used to connect from the matrix blocks to telephone ringer leads. Brown was used for AC supply to buzzers, and white was the switched ground from manual signal buttons.

House cable pairs were home run from the MDF in the switch room, with enough pairs (generally 100 or more) to each floor. In the event that features from one floor needed to be assigned to telephones on other floors, they were never run floor-to-floor; they were run, via house pairs, to the MDF, cross-connected, and then run back up to the other floor via the house pairs for that floor. There were no inter-floor pairs installed, or allowed. There were about 4,000 house pairs just for the main building. The switch room housed the 701 PBX of 6,000 extensions and the 100-foot long MDF. The battery room was on another, lower, floor. The main room was approximately 120 feet by 60 feet.

Every main and satellite closet used the appropriate color-coded backboard system. Each main closet had a talk wire with auto ring-down circuit to the MDF key system.

House pairs were strictly documented (as were all feature assignments and lateral pairs). House pairs might carry a CO line, a PBX extension, or a feature from floor to floor. Of the seven people working full time at the location, only two were allowed to work on the frame, or make entries into the wire log, without supervision.

These rules may seem silly now, but the adherence to the rules was the only thing that kept the whole place from descending into chaos. Other installations of similar sized systems used many more persons-to-stations and had a much higher trouble rate per station. Our well-regulated system worked the best.

I don't think that the rules sound silly at all . I think that this is the way all installations should be done instead of the total chaos that goes on in the "closets" (at best) that we get these days.

Just like when you hear of kids using the "F" word to their parents these days, respect for any form of regulation has gone completely out the window. It's a shame.

Thanks very much for the accurate depiction of how any large installation should be done of any kind. I enjoyed this reading.

Arthur, do you have any pictures of this install or one similar? It's hard for me to imagine something so large in scale...

Arthur -

That is absolutely the right way to do it. No, the rules don't seem silly now at all. At least not to me. A well run, well organized plant runs better, smoother, much more efficiently, with a much lower incidence of repairs and problems.

Unfortunately - try convincing senior management of this. If it can't be quantified then they're not interested.

"Less problems" is not something you can sell these days.

One of the reasons I'm not running Telecom at the Bank of New York anymore was my insistence on Installation Standards and Preventive Maintenance. Management at the bank couldn't justify the expenditure to their bosses.

There's an old Latin expression: "Sic transit gloria mundi"

Translation: Gloria took the train to work on Monday.

Well....not quite.

Real Translation: So Passes the Glory of the World.

My favorite expression during my last days at the Bank was from an old traditional blues song:

"I know you rider, you're gonna miss me when I'm gone"

And they did.

I didn't miss them. Just my expense account.

But the real point of this whole thread is that properly done work, well maintained looks good, is easy to troubleshoot and just works a whole lot better.

Sorry for the rant and the hijack.


Sam

Blues song? That's Led Zeppelin!!!

Thanks Arthur for that detailed write up - I have a better visual of it now.... sure would love to see something like that in person. The home run rule makes alot of sense to me... in my setup it's really not critical, but I can see in a "real" application how pulling one bridge clip and shutting down an entire floor or more ..... just might cause an issue.

Also it helps answer some questions I had about troubleshooting.

And once again - thanks to everyone else who commented. I've got the ringers back online. Intercom next weekend. I'm too punched out to even think of touching it today. .... I don't understand how you guys could do punch downs for 30+ years.... seems to me your hands/wrists would be worn down to a nub.

One last thanks...!

Matt

Above all in large installs document,document, and document.

Yep - even in my small system... this is another thing I did this time that I didn't before.