Q.: 10-button deskset w/ 50-conductor line-cord [Telecom]

Sounds like a 10-button KTS wall set. Seems WECo used the 8xx designation.

I don't recognize the "hipped" description though.

Post a picture in x.binaries and I'll have a look-see.

We don't publish images in messages (sorry), but I'll be glad to put it on the TD website for a day or two.

Bill Horne

Bill, would you please post a URL for this site?

TIA.

Does it look like this ??

Done, under the Subject: line "Conjectural WEco KTS wallset photo".

Bill, thank you: I've emailed you a jpeg photo of the unit, likewise with Subject: line "Conjectural WEco KTS wallset photo".

Yes, a link to that pic once it's up would be welcome, please; thanks.

Cheers, -- tlvp

The image is at

If I recall correctly; it was a non-WECO keyset. I think AE made them. I can't recall the name, but the distinguishing aspect was unlike 2565 series sets, it used fewer conductors.

A 2565 plug was wired:

{Pin #

T-R A-A1 Line one L-LG

{4-29} T-R A-A1 Line two L-LG

etc. which limited you to 5 lines per 50-pair jack, once you included the special pairs needed for various things such as speakerphones.

So sets with more keys [such as the SecDef's and POTUS Call Directors ..] needed multiple cables..

The pictured set was wired:

T-R Line one A-L

T-R Line two A-L

with common grounds for A and lamps. This saved on cabling, at the cost of the lamps getting dimmer as more were on.

Thank you, Bill! And cheers, -- tlvp

Toward the end of the Bell System era, WE developed various new lines of keysets that looked something like this. Many had more lines than the traditional six button. They had bigger square buttons with the line label as part of the button and lamp, no separate strip. They came in both rotary and Touch Tone, desk and wall version. The wall versions had the hookswitch on top.

Some were part of systems, such as the ComKey system which had various special features and was an advanced key system. ComKey came in three specific sizes, the big one had three separate intercom paths and PA system as part of each set with the tone ringer*.

Others, AFAIK, were just jumbo keysets able to handle more lines.

These were the last of the incandescent line lamps and thick cords style sets. They later went to LEDs, internal chips, tone ringers*, and thin cords, like Horizon and Merlin key system. Sorry, I can't get used to calling something a "voice terminal".

• The Bell System for years was trying to dump mechanical ringers for electronic tone ringers to avoid shooting the high voltage ringing current through ESS circuits, but it wasn't until the 1970s that they could come up with a suitable workable substitute. Tone ringer sets were tried in Morris.

O.K. I got here late, but the numbering is consistent with ITT, unless...13 is that lvoely shade of moss green, BA is straight line ringer, 42 is ....can't remember but has to do with key type and the M has some meaning, probably dial....I can look it up in my ITT book if it's important. 3/76 is obvious.

The 25pair amphenol is probably cabled out the same as any 10-button set and linked here.

You'll probably not get that far, but the voice pair for each key is always offset 3, the A leads start alternating as 2,9 3,8 4-7 and 5,6 The lamp leads stay in position as pair 3,6,9,12,15,18,21 24, and 23 :-) That leaves the 17th pair (buzzer) and the 20th (bell).

easy, Peasy.

Carl

Whoops, forgot to mention that one of my buddies (Jeff "Mooseman" Moss) on Facebook just nabbed a Lunchbox/Shoebox KSU that he'll probably let go for cheap. It would be something fun to play with.

cn

Thank you, David. Can I now learn, please:

(1) where the supply voltage for the Lamps came from? (2) which of the "line" pairs were dedicated to CO lines, and which for on-premises "extension phones"? (3) what ancillary peripheral equipment was needed to route a given inbound call to a given on-premises extension phone?

TIA; and cheers, -- tlvp

Speaking in general terms for key systems:

The key system unit had a power supply. It took 120VAC and converted it to lamp current, intercom current, and ringing current.

Key systems generally did not have "extensions", all phones had some CO line access. In many installations line access varied by station. In others, every set accessed all lines.

There was of course the red hold button. Other buttons could be assigned to lines (either CO or from a PBX), intercom lines (dial or push button), and other signalling arrangements. Some advanced key systems had special features, for example, the ComKey system had a 'privacy' button which prevented other extensions from listening in.

In key systems call generally were not 'routed'. What usually happened was that someone answered the phone, pressed the hold button, dialed the desired station on the intercom*, and announced the call. The recipient would punch the line button and take the call. The receptionist could've easily yelled across the room or used a loudspeaker, "Mr. Smith, call on line 3".

Some intercoms were not dial, rather, there was a separate series of push buttons which manually sounded the buzzer. These buttons could be added to the side of the phone or [might have] been unused line buttons.

Note that sophisticated key systems of today mirror PBX functions.

Note that certain phones that look like giant keyset Call Directors were actually PBX consoles. They usually had a separate green square next to a line button.

I once connected a 660 comm panel to a key system, and I wired all the "LG" leads together - "LG" meant "Lamp Ground", right? It didn't work, and the local installer they called in to fix it told me "LG" means "Lamp _Gain_", and that the "L" leads were all common, with the LG wired to each KSU's lamp lead.

Was this a practice peculiar to N.E.T.&T, or was that the standard?

Bill

No key system unit (KSU ?) accompanied the telset I have. As a single stand-alone desk set on one line (using just conductors 1 & 26), is a KSU even needed? Would a basic Bell System 6V AC (or 12V AC) wall-wort transformer suffice for the lamp current?

In my single-line household, I guess questions (2) were just academic.

Ah-hah! Thanks for making that question bite the dust :-) .

Thanks very much, hancock4! And cheers, -- tlvp -- Avant de repondre, jeter la poubelle, SVP

You may use a multi-line set as a regular phone instrument by simply wiring the tip and ring to the line(s) in question. However, the hold function, lights, and intercom all depend on separate KTU equipment.

It is, of course, possible to use a wall wart to power the lights, but you'll have to rewire the a leads so that they are in series with the lamp, because otherwise the lights will just be on all the time.

And, nobody has said anything about my quesiton on "LG" leads. I am _eagerly_ awaiting the answer!

Bill

Thanks, Carl, for this clear pin-out PDF.

Yeah, "easy, Peasy" -- once you've got the pinout diagram :-) .

Thanks again, very much. And cheers, -- tlvp

It's important to remember that the HOLD button won't work without a KTU. But having it on a phone means there's a tendency to use it, and in this case [that] would cut off the call.

Sometimes the hookswitch has unused contacts which could be used to turn the lamp off and on.

Historical Note: In the 1970s, keyset line lamps were an option. Most places had them, but plenty did not to save money. Further, 'wink hold' was a further cost option. Older installations tended not to have it, while newer ones did.

Question on telephone public address systems: I've seen several installations where access to the building PA system was directly through the telephone. In one, the PBX operator pulled a key. In another, it was one of the intercom levels on a key system.

Would anyone know if the PA systems so provided were provided by the phone co or customer owned and linked in?

In the case of the PBX operator page, it would've been just as easy (and done in places) to have a regular microphone at the operator's position.

You're right, and it bears mention that it can't be disabled: the hold button has a mechanical linkage to the line buttons (they are spring-loaded), and it releases the catch which keeps the line button down.

Some multi-button sets also had a mechanical linkage which released _all_ the line buttons when the hookswitch was depressed. Does anyone know which one(s)?

I'd advise against trying that route: you'd have to go into the phone and move wires around, and it wouldn't control the light on a particular line. The "A" leads are available at the connector, and they are switched by the "Line" buttons.

There were instances of company PA systems which covered multiple buildings, where the PA systems in each building were linked via dedicated locals pairs tariffed for the purpose.

In a few cases, testbored (pun intended) technicians would cross-connect racy phone calls to the PA lines, thus broadcasting the intimate details of various employee's lives to the whole company.

Bill

I believe on the ComKey it did that.

I recall reading a Bell Labs Record article on that; for its day (mid

As mentioned, the high-end key systems like ComKey overlapped low-end PBXs, with the big advantage that no PBX operator was required. Also, of course, newer systems like ComKey offered installation, maintenance, and cost advantages to the operating companies. As time went on, systems became more and more modular and 'plug in'.

ComKey may have been the last key system using incandescent lamps and thick cabling.

But, 99.9% of the subcribers served by an ESS don't have key sets. Standard ringing voltage has to be sent from the ESS to them, even today.

Electronic computer circuits, such as within an ESS, do not do well with the voltages for voice and ringing, so the switches had to work around it. As mentioned, one attempted solution was using low power ringers, but that didn't work. Ironically today most telephone set ringers are lower power than the traditional 500 set mechanical bell.

I am hazy on the details, but certain keysets and ESS didn't mix well. To handle switching, battery would be cut out for a fraction of a second so that power wouldn't live when the switching occurred. But this battery cutoff fooled certain key systems into thinking the line was dead and they'd drop out.

Yes, but, the LEC can't assume there are no longer 500 sets or similar out there.

I remember it well. It was the 1 and 1A ESS machines that had an open battery interval as the connection was dropped and battery was transferred from "clean" voltage to lesser quality voltage. But, that would drop a held line on a KTS, which was good. The "bad" came in with three-way calling and call waiting. There was also an open battery interval with those two features when transfer was made from two-way to three-way porting or the other way. If a KTS line was on hold and had call waiting, a call waiting coming in would drop the hold, thus dropping the call.

There was a fix, though, by changing out the line card to a modified card that would not drop a call on open battery interval. In my area Pacific Bell only fixed this issue upon complaint.