Classic Rotary Phones Forum

Telephone Talk => Collector's Corner => Topic started by: Dan/Panther on June 24, 2010, 03:09:09 PM

Title: Help ID this phone.
Post by: Dan/Panther on June 24, 2010, 03:09:09 PM
Is this phone a WE or Kellogg ?
What does zone 5 only mean ?
Title: Re: Help ID this phone.
Post by: Kenny C on June 24, 2010, 03:12:55 PM
i was wondering the same thing i seen that on ebay.
Title: Re: Help ID this phone.
Post by: LarryInMichigan on June 24, 2010, 03:14:10 PM
What does zone 5 only mean ?

It means that the phone can only be used in Michigan.  You had better send it over here.  You wouldn't want to be taking any chances using it in the wrong zone ;D

Title: Re: Help ID this phone.
Post by: Dan/Panther on June 24, 2010, 03:17:13 PM

Ditto again.... ;D ;D ;D

WE or Kellogg.
Title: Re: Help ID this phone.
Post by: Jim Stettler on June 24, 2010, 04:42:13 PM
Zone has to do with (wire) distance from the CO.  500 sets worked at greater distances than 302's.

There are some bsp's that explain zones. I am thinking the higher the zone # the greater the distance from the CO.

Title: Re: Help ID this phone.
Post by: paul-f on June 24, 2010, 09:12:36 PM
Let's try BSP searching again!   :o :o :o

1. Look in the general numeric index to guess what division it might be in.  (By now you know how to find the BSP Library)

2. Guess it might be in Division 500 - Station Equipment, more specifically 500-000-000 - General Considerations for Station Installations.  Find and read the Division Index.

3. Click on the entry for 500-110-100-i5-TransmissionZoning.pdf

Well done!   :) ;) 8)
Title: Re: Help ID this phone.
Post by: Jim Stettler on June 24, 2010, 09:36:53 PM
I like your approach to BSP tutorials, I suggest you keep it up. Maybe it is worthy of a new board.

BSP are like code books, all the info is there IF you know how to find it:
ie: a 500 is a station  set
A card dialer is a Specialty set.

The only way to really learn BSP"S is to PRACTICE using them.
The index is the most broad based way of learning them.
To find the "proper" BSP for your 500 type set, use Paul's site as a cheat sheet.

Title: Re: Help ID this phone.
Post by: GG on October 15, 2011, 10:02:49 AM

Why the zone stuff:

WE 500 K (J/K 500) had a network of roughly 425-A vintage without the equalizer, and had a set of plain terminals to the left of the network block where the equalizer would otherwise be mounted on these early 500s.

Thus 500K had no line compensation, and took full advantage of the increased efficiency of both transmitter and receiver.

For this reason, on a short loop the sidetone level is VERY loud (as in, I like high sidetone, but a J/K 500 on a PBX even a bit too loud for me).  And the transmitter output is also probably too loud, to the point that the person you're speaking with could probably hear you breathing, which is disconcerting for most people. 

Zone 5 was the furthest zone from the central office: the longest loop.  Putting a J/K 500 in zone 5 would have the same effect as putting an A/B 500 there (with the equalizer):  on the A/B 500 (or C/D 500) the equalizer would adjust itself to the condition for highest transmitter output.  J/K 500 achieved the same result at lower cost, saving the more costly A/B or C/D 500s for closer-in zones where automatic compensation was useful. 
Title: Re: Help ID this phone.
Post by: gpo706 on October 16, 2011, 02:00:22 AM
GPO 706's had regulator slide in boards to accommodate the distance from the CO line, is this maybe a similar thing?
Title: Re: Help ID this phone.
Post by: GG on October 16, 2011, 03:32:02 AM

Not quite similar; J/K 500 was an earlier way to adapt to the post-WW2 expansion of suburbs that were at the limits of loop length from their nearest city central offices.

WE A/B 500 was originally designed to self-compensate at any distance from the CO, with the relevant components (WE: "equalizer") mounted in a small additional metal enclosure in the phone.  J/K 500 was intended as a lower-cost way to deal with long loops, saving the cost of the equalizer altogether for phones on long loops.   

When lower-cost and more compact metal-oxide varistors became available, WE incorporated them into the transmission network block assembly, as the 425-B network, and did away with the separate equalizer unit.  At that point the cost was low enough to make it possible to include in every phone (by this time, C/D 500), and not have to worry about loop lengths. 

All of the above occurred in the time frame 1950 - 1955 or so.

GPO had the benefit of all of this history before designing the 706 in 1959.  At that point the cost of the regulator electronics was already low enough to be worthwhile including in every phone.  The PC board design enabled creating the built-in "non-regulated" side of the circuit board for virtually no extra cost, for the relatively rare cases where it was useful to have that option. 
Title: Re: Help ID this phone.
Post by: Wallphone on October 16, 2011, 07:59:52 AM
For more info on Zoning go up to the Paul-F posting from June 2010 and click on BSP 500-110-100-i5. In that BSP is this chart.
Doug Pav
Title: Re: Help ID this phone.
Post by: GG on October 16, 2011, 11:11:50 AM

Notice the loop limits:  zone 2 is basically 2 miles, zone 5 is basically 10 miles. 

And notice the 500 set in the middle, trailing the round ball labeled "equalizer," with the quote balloon "I don't belong in this zone for supply reasons."  Translation:  302s still work here, keep using them as long as possible, conserve the 500s for the zone that's beyond the limit where 302s will work.  (302s including 5302s, to provide a more modern appearance for subscribers who want it.) 

There's an older version of that chart around, with more 302s shown, and minus the Trimlines.  What I find surprising about the version you posted is that even when Trimlines were available, Bell was still balancing its inventory of older sets by assigning phones to zones.  Implied: there were still 302s going into service in some places as late as the mid 1960s.  Born out by the occasional appearance of 302s on Ebay bearing original "modern" number labels showing area codes and numeric exchange prefixes. 
Title: Re: Help ID this phone.
Post by: Wallphone on October 16, 2011, 12:26:15 PM
GG, Maybe the other chart you mention is in an older version of BSP 500-110-100. The one that I posted is from Issue 5, 1965. Only Issue 5 & 6 is in the TCI Library. In Issue 6 they don't have this colorful chart, only a grid.
Doug Pav
Title: Re: Help ID this phone.
Post by: paul-f on October 16, 2011, 01:23:37 PM
While we're on the subject...

I love the graphics in the Issue 3 chart!   :o
Title: Re: Help ID this phone.
Post by: GG on October 16, 2011, 10:51:45 PM

The phrase "a shot in the arm" goes back to the early days of antibiotics, where a single penicillin shot worked wonders, and bacteria had not yet started becoming resistant.  It became generic for "something that makes you better, quickly." 

These charts tend to explain why suburbs got the 500s more quickly than central city areas (that could use 302s within their designed loop limits) or even the rural outskirts of cities (302s served by transmission equipment along the cable spans).  It was all about balancing out the most efficient uses of copper cable, transmission equipment, and telephone sets.  At one point in the 50s there was a copper shortage, may have been related to the Korean War, so the careful balancing of equipment enabled meeting demand for new service more rapidly than would have occurred otherwise.     
Title: Re: Help ID this phone.
Post by: AE_Collector on October 16, 2011, 11:19:49 PM
Not sure if you would get 10 miles in zone 5 on anything other than very heavy gauge cable. 26 milliamps or 23 ma absolute minimum current flow is considered the lowest current flow acceptable.

Interestingly they would always use light guage (26 ga) cable around the CO and then go to 22 ga further out and finally 19 ga way out from the CO. The heavier gauge cable that fed the distant locations didn't go all the way back to the CO, it was spliced onto the ends of the lighter gauge cable that was in the close vicinity to the CO. Doesn't matter where the heavier gauge portions are located so the easiest place to put it is at the distant end of the run.

That's the extent of my outside plant engineering knowledge!

Title: Re: Help ID this phone.
Post by: GG on October 17, 2011, 03:34:09 AM

Oh the things we can get away with, in the world of low voltages!  Such as splicing larger-gauge conductors onto the ends of smaller-gauge conductors! 

Yeah my knowledge of outside plant is limited too.  Unlike switching systems, you can't just build an entire outside plant distribution system in your basement, so the only people who really know it are a small priesthood in the telcos.