Found at the The Herbert H. Warrick Jr. Museum of Communications:

This last Sunday Dave and I went to the Seattle Museum of Communications for a tour. It's in a working Central Office in the Georgetown district of south Seattle. This is not your normal telephone museum, they have actual working examples of various CO switches through the years.  To get in you drive to the back of a nondescript building (it's a CO after all) and enter through a side door to take an elevator to the third floor.  Ed greeted us as we stepped off the elevator and asked how much time we had.  We said at least two hours.  He smiled and then started us off on his tour.  The first stop was at a step-by-step Strowger community office row of racks where he described each section and its function. He then picked up a phone and made a call on the switch and we watched each section in action as he dialed.  Needless to say I had to have him do this slowly several times so I could track each stepper through the process.  With the step-by-step switch this was easy to see and follow the logic.

The next switch section, and by section I mean several rows of 12 foot racks, was the panel office and its rotary sequence switches.  Sad to say, this was not working that day but he gave a wonderful explanation of its operation.  

Then on to the #5 crossbar office.  Again he explained and demonstrated by making a call.  Such wonderful and inventive equipment.  Racks and racks of mechanical relays all wired in to a subtle logic to complete a call.  So, the question arises, in such a complex system how do you know if there is an error due to a bad relay or other device?

Behold the No. 5 Crossbar System Trouble Recorder Card.  The #5 crossbar system has an automatic monitor test frame that will detect a stuck relay or other malfunction and cause a device to punch holes in this card for the tech to find and work a trouble ticket on.  This would allow an office to be unstaffed nights and weekends, saving much overtime cost.  Of course it took about 18 months of training just to start to figure out what the card was telling you.  After a few years you would just listen to the switch and know when it was off.

What is so amazing about that trouble card is that those racks and racks of relays not only can connect hundreds of calls and bill the long distance, but they also know when they fuck up and then open their own trouble ticket. 

This is all without a freaking computer or any semiconductor logic.

This was designed in 1963.

What type of geeks were these engineers?

We then went down to the second floor and looked at an ESS 5 switch, not much to see except a bunch of card racks just sitting there.  Then on to the collection of outside plant equipment, old phones, trick phones, PBX systems (a full crossbar PBX!) and a collection of toll and teletype equipment that would make any geek happy.  I think they have every configuration of a Model 32 Automatic Send and Receive (ASR32 for the hackers)  teletype ever made.

If you are in Seattle on a Sunday and you actually read this whole post, you want to see this place.

TheBellSystem.net: a place for those that love the equipment of the pre-breakup days.

The focus of this blog will be old Bell System and Motorola equipment.  Sometimes I may get into other classics of the era like GTE, RCA and GE.  I'm a child of the 70s so this isn't so much about the Bakelite stuff but think more the era of the classic WeCo model 500 dial telephone through to the breakup.  Of course if I find a nice oddity I'm going to talk about it.  Let's start with one of those.

This little station is an Automated Electric GTE branded unit stamped with May 1976.  Was this for when they didn't accept DTMF at the CO but you may still need to send tones for some "Touch-Tone voice answer back" system?  That's the only use I can think of.  Still, it speaks of an era when DTMF was just getting rolled out to offices.  I remember that one office in Selah, WA (509-697) run by the Ellensburg Telephone Company would translate DTMF to pulse for their switch.  When making a call you could hear the translator in the CO pulse dialing (about 20pps) to the switch after the caller sent a DTMF signal.   Maybe not so strange, a lot of phones sold right after the breakup had obvious "Tone/Pulse" switches to swap between setting up the call and then using tones to talk to a banking system.  Anyway, it's a nice little station and I'm sure the top bidder will be very happy with it.