Telephone Ringers: how & why

I would suggest reading the first volume of the Bell System "Engineering & Science" history. It's available in larger libraries. That goes into detail about the development of the earliest telephone instruments and components of each instrument. The local loop is part of that discussion and may also answer your question. (They spend a great deal talking about the pros and cons of loading coils, for instance.)

As to my earlier comment about "fence posts", I meant wire fencing using in some rural areas which was used as a telephone conductor. Obviously not the best.

As others pointed out, plenty of telephones with mechanical readers are in service. My office uses literally hundreds of plain vanilla

2500 sets.

Another factor in signalling is the length of the local loop. Several people mentioned PBXs, but the requirements of loops in a PBX are usually much easier than that of a central office (per the Bell System history 1925-1975).

Thankfully all my experiences were with real VT100 and DG D416 terminals.

Our office is mostly 6480D+'s, followed by 7406D and D+'s, and a few

8410D's.

No analog sets at all.

(Some snippage here)

In many cases, for reasons pertaining to switch hardware or cable plant, party line customers were graded over to "private lines" (or more correctly, single party lines) but their billing remained as multi-party, just as they'd been for years. That way the Plant Department was happy (no more party lines) and the customer was happy (lower rates for "party line service"!).

Better; BTL/WeCo came up with "bridge lifters" -- a way to make parties on 2 diverse cable legs parties on the same assignment.

So they'd be able to keep anyone play for party line service exactly that, and no more....

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that\'s close........[v].(301) 56-LINUX
Unless the host (that isn\'t close).........................pob 1433
is busy, hung or dead....................................20915-1433

And it was a real bitch troubleshooting when someone left a gate open.

TerryS

David Lesher snipped-for-privacy@panix.com posted to sci.electronics.design:

Wow, a lot of interesting history has come to light in this conversation. How about storing it in Wikipedia as well.

The ringing frequency had nothing to do with the response characteristics of the bell mechanism at all. I think the frequency has more to do with the precursor to the introduction of motor generator ringers, ie. the hand operated magneto.

The magneto design was a compromise in several aspects, one being to make the gearing so that it was not too hard to turn by hand for all users, even the elderly, while rotating the armature at high enough speed to produce around 70Vrms.

It also had to be a simple design to reduce cost, hence a 2 pole 'H' shaped armature while using 'U' shaped permanent magnets to supply the field. As it turned out these compromises resulted in a magneto which resulted in an output frequency of nominally 15 - 20 c/s (Hz) which was considerd adequate to operate a polarised electromagnetic bell mechanism with a striking hammer and two gongs resonant at different frequencies. In the UK a nominal frequency was 16-2/3 c/s (rounded to

17c/s) was adopted as the standard ringing frequency and more recently this figure was changed to 20Hz to conform with an internationally adopted standard. The bell mechanism which became the standard was optimised to respond to the frequency produced by the hand magneto and when motor generator ringing machines became the norm for automatic exchanges they had to be compatible with telephones using the same bell mechanism.

It may also be of interest to note that the 2 pole 'H' armature in the hand magneto was deliberately shaped to produce a 'spiky' representation of a sine wave because this was more effective at producing a rapidly rising magnetic field which would overcome the permanent magnet bias in the bell itself and thus produce a 'heavier' gong strike.

My late father had lived in Rochester, NY while working at Kodak in the way-back days. He remembered manual service before being transfered to Chicago for a year or so. He returned to a Rochester suburb in the town of Irondequoit, and by that time, the Norton St (ROCHNYXF) office might have been converted to #5XB, or shortly after his move in 1960.

It appears that the "closer to downtown" offices had #1XB early on and the five outer offices received #5XB as time went on.

How Rochester Telephone, a major independent operating company, fanagled Western Electric into providing switches is probably best left as an academic exercise. My aunt, who worked for RochTel for many years, doesn't know the answer to that. Later, she did get me an old Kellogg

2554 set with an S-C G-type handset which I got to use while living on my own.

Then my and my aunt's cousin lived in an outer suburb of Webster. She had a party line back in the '70s as I remember seeing her S-C 554 wall set in the kitchen, clearly showing a "party line code" on the card insert. What type of office Webster had is unknown.

--
Curtis R. Anderson, Co-creator of "Gleepy the Hen", still
"In Heaven there is no beer / That's why we drink it here ..."
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Graybar was the WECO outlet to non-Bell telcos. Anything you wanted could be purchased there.

Graybar is still in business,

selling communications and other products.

They were one of the last companies to have a working Enterprise toll- free number.

(Enterprise, known by a number of names, UX, WX, was the toll-free service before 800 numbers, dating from at least the 1930s. You asked the long distance operator for the Enterprise number, she looked up the actual number and placed the call, automatically billing it as collect. In the waning days numbers were still listed in white pages but most were non working (the listings never got purged). AT&T operators, the only ones who could make the connection, usually had no idea how to do it and had to get a supervisor to dig out the translation book. Given the much cheaper cost of dialed direct 800 calls, I'm surprised Enterprise numbers lasted as long as they did, into the 1990s. For some reason most of the remaining listings belonged to heavy industrial supply companies.)

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a database, which sends back the Switched Network real number. That is, unless they have modernized the method.

Anybody know if the California and Nevada Highway Patrols are still accepting calls to Zenith 1-2000?

A quick look at their web sites doesn't show the number but it could just mean they're tring to phase it out.

--
					-- Rod --
rodd(at)polylogics(dot)com

A couple years ago the "official" Nevada state highway may referred interested parties to the Zenith number. I don't know if that still works or not - I'll be in Reno in a month or so and will try it out and report back!

Al

Zenith was another name for Enterprise. Also was UX and WX.

It's not so much if they'll accept the call as the called party isn't asked, it automatically goes through.

Rather, it's more if an operator today knows what to do with that request. Even back when the service was still working most operators didn't know about it, and one had to insist on a supervisor or senior person who knew about it, then they had to dig up the conversion table.

I believe someone said Alaska police used it as well. Don't know if still true.

With the advent of cell phones there are now usually three button calls for state police etc. In RI it's *77 to reach the Rhode Island State Police.

I love the assumption that there IS an operator. With VoIP you get no such beast.

snipped-for-privacy@bbs.cpcn.com wrote in news:1188423595.346609.33720 @k79g2000hse.googlegroups.com:

Oh, I remember that.

The Ontario Provincial Police were Zenith Fifty-Thousand.