In the days of the old electro-mechanical telephone network, most exchanges of any size had these test numbers. The term "supervision" comes from the old operator cord boards on which there was a lamp for each line. When that line was in the "off-hook" or "answered" condition, the supervision lamp on the operator's board would light up, letting her know the line was in use. As time progressed, and after Direct Distance Dialing (DDD) came out, then people could dial their own long distance calls. In order to keep track of how long they talked and then to bill them accordingly, some automatic way to monitor the "supervision" of every line had to be implemented. ---------------------------------------------------------------------------------------------------------------------------------- In this way, the old "supervisory" lamp circuits for operators slowly got redefined and used for billing. In a step office such as mine, when a called line answers and goes "off-hook" the line DC polarity reverses. This is known as "reversed polarity supervision". It can be seen in this video on the ammeter which monitors the testboard's outgoing line. That meter has zero at the center. RIGHT of center is STRAIGHT line polarity with Tip being positive and Ring being negative. When the meter needle passes through zero and goes left of center, that is reversed polarity. Remember it this way "Left is the REVERSE of normal". ------------------------------------------------------------------------------------------------------------------------------------- So a supervision test is a number that when called acts like someone picking up and hanging up a phone. Its purpose is to test the action of the supervisory relays. Hope this helps explain. Please go look up Evan Doorbell and all of his old phone tapes. He explains it all in much greater detail. Keep the questions coming guys! I am happy to answer them all!

Yes. Card #4. Sweep Tone Tests. There are two sweep tests on that card. Coming up soon. Stay Tuned. 😎

Yes that is likely true too. Back in those days, some long distance trunks were fairly faint, rather noisy, and low in level. Then after a few of them would be stacked end-to-end as was done quite frequently, the transmission was not only low in level, but quite flat in frequency response as well. It then amounted to a very tinny sounding, far away, noisy connection that sometimes was difficult to talk through. Operators in those days were required to pronounce numbers in a very specific way to be understood through such connections. Instead of just saying "nine" she would say "NYE---Uhhn". Not unlike the phonetic alphabet and numbers used by pilots and military. (they say nine-er). But that ubiquitous "BAWWWWP" of old city-dialtone burst when a long distance call picked up was a big part of my boyhood telephone memories. So I brought it back on my private exchange, so that we can continue to enjoy it! ⚔⚡⚡

@@leroyjones6958 I was an AT&T TSPS operator in summer 1987 and there were a few old biddies in the office who had stories! Apparently they used to "accidentally" brush a colleague with ringing current on a cord when bored! (I then moved on to 1A2 installation, and eventually PBX's like Horizon and Dimension - all gone now!) Love your setup!

@@AlexisKasperavicius Oh yes. I remember when TSPS was brand new! We phone phreaks called it "tiss-piss" because it thwarted many good old hacks such as down-upping the hookswitch at just the right time to interrupt the ANI MF spill that the 4A machine downtown issued out to the CAMA equipment. We called this humble procedure "CAMA Fraud" and here is how it worked: After down-upping the hookswitch just as the 4A was about to go "ka-BEEP-click", there would be a long delay, a ring, and then a CAMA operator would come on and ask for the originating number because ANI failed so now they must ask. Well it turns out that in a crossbar #1 office such as my phone at the time was in, those CAMA operators could accept anything in the local marker group of the originating exchange. In my case the local marker group consisted of (4) prefixes so that amounted to my choice of 40,000 numbers to give her. As long as it was in this group, the call would go through after she entered it. I'd usually give her a test number such as a sweep tone or loop-around or something. ---------------------------------------------------------------------------------------------------------------------- TSPS put an abrupt end to that. But then a few months later after high school a girl I knew from school hired on as a TSPS operator. I would dial 411 and play operator roulette until she answered and I'd say hello to her using her name and she'd freak out until she realized it was me! Because back at that time they routed directory assistance out to the then brand new TSPS center. Good times. -------------------------------------------------------------------------------------------------------------------------- It all went away. So I have had to build my own. I do also have a little 1A2 that works in a 5 member hunt group in the stepper.

The thumbwheels are used for setting. The smaller clock is much simpler. It only has 17 ICs total. It uses (6) of the 74HC160 synchronous counters. In an effort to minimize complexity and parts count, the thumbwheels also serve as the number loaded on the next clockpulse after either 23:59:59 (for 24 hour mode), or 12:59:59 in 12 hour mode. As seen in the video, it is operating in 24 hour mode, so the thumbwheels must be left at 0000 so that it goes to that at midnight. If it was in 12 hour mode, the thumbwheels need to be set to 0100 to make it work correctly. When ever this clock gets set, those wheels must be returned to those values otherwise timekeeping won't work. ----------------------------------------------------------------------------------------------------------------------------------------- The other larger clock uses about 42 ICs and is much more complex. It has a settable alarm. The keyboard is used to set time, set alarm, turn the tubes on and off, select 12 or 24 hour mode, and keyboard also controls the seconds counter, zeroing it then holding it until time to turn it loose. When I built that one in 1994, I wanted an easily settable clock. Just punch in the numbers. Easy to set, hard to build. it is all wirewrapped. The larger older clock uses a pair of 74LS160 counters for seconds. Minutes and hours are 74LS192. Those turned out to need help resetting to values less than ten, with the aid of 74LS221 pulse maker (monostable multivibrator) to assure a reset pulse of a defined interval instead of attempting to reset on a spike. I realize now that 74LS192 is not an ideal counter to make a clock out of for this reason, but it's done long ago, works real well and so I leave it that way. The most recent effort, a clock based upon the rare 74142 counter/driver........it needs help too. had to actually add 3 more counters to "supervise" the 74142s. But that clock operates ok, and the parts count for it is 16 ics. So I actually beat my old record of fewest ICs by one IC. Those old old TTL counters are hard to reset properly on the fly to make them be modulo 6 instead of modulo 10, and then the entire modulo 24 business gets even stranger yet. But a 4024 binary counter came to the rescue there, because bits "16" and "8" are ANDed together, so it spits out a nice pulse when N=24. It needed a 74HC221 to make a solid reset pulse of 100 uS. 74142, by far not the most efficient way, but has it ever even been done before? I wonder.

@@leroyjones6958 That's Genius. Thanks so much for sharing and inspiring.

Nope. I wish it did but since there is only ONE of the Digitalker units available, when ever the bus controller assigns one of the 8 ports of Digitalker, to one of the specific applications, all of the other 7 remaining ports are held in a waiting que until Digitalker is again available after the first call disconnects. It is a "first come, first served" type of arrangement. For instance it is set up so that when Digitalker is busy elsewhere and the talking clock line is called, it will not even answer the call until the bus is selected for Digitalker to be assigned to the clock. It is 8 ports, but only one at a time can be serviced. (it is expandable too by the way, if it ever needs 8 more) 😎

@@leroyjones6958 Wow, thanks for the write up! Very interesting-and such a beautiful setup you have there. Looks like a lot of fun! Please keep the videos coming! :)

The diode matrix translates a "1-of-200" contact closure into an 8-bit binary number. (two hex digits). The hex line ID numbers range from 01 through C8, with 00 reserved for testing. Since there are 5 linefinders, the ANI must scan across them until it finds the one which has the call to the ANI. That happens when you hear those fast little beeps. The beeps are the ANI scanning. Once the proper linefinder is identified, then a 48 volt signal is sent to back jack pin 5 on it. That 48 volts flows through the linefinder and then out on either the A or the A1 bank wiper, which has landed upon those bank contacts which represent the line I.D. of the calling line. That signal then flows through a 200 conductor cable, over to the diode matrix, which generates the 8-bit line I.D. code, which it then sends over to the ANI on those 3 boards on the table across the room. There, that 8-bit line I.D. code then gets turned over to a 2732A EPROM which has been programmed to act as the translation table that contains all of the phone numbers associated with all 200 of the 8-bit line I.D. numbers. Those phone number digits then get passed along to Digitalker so it can be spoken and at the same time it is fed to the flashing green 7 segment readout, which shows the calling phone number one digit at a time as it gets spoken.

Thank you! It was a long hard slog. The first time it talked was really glorious. That came after 2 months of work. It has been in service in its temporary configuration now since 2015. Most of the bugs are out of it now. :)

Thanks! Just swapped out several of the old 7400 style ICs in that RatShack keyboard. Installed a variety of CMOS ones such as HC, C, HCT, and had to settle for a few LS ones in sockets where none of the CMOS ones seem to operate correctly. But now have total keyboard current down to 90 mA, where as originally it sucked up 450 mA!