Well, I finally got my 551C hooked up and was able to find a couple boxes of 1A2 stuff, none of which I think I can use.
I just found something on the internet that says the only line cards you can use in a 551C are the 400, 401, 415, and 467. Is that true?
Can someone remind me of the difference between the 401A and 401B?
What does a 415 card do? The BSP says you can only use one per KSU. Why? Not that I would probably have need of more than one.
What does a 403 card do and could it be used in my 551C?
If I remember correctly the 415 was a ring down card for special point to point circuits..sort of a hotline. But it has been a while. A LONG while.
OK. One at a time...
1. I don't think that's exactly correct, but I'll have to check.
2. A 401A requires an "A" lead to function. A 401B does not.
3. Dave is correct. A 415 is an automatic hotline card. You need an identical card at the far end. Pick up the line and the far end rings. Unless it has been (unofficially) modified it will only work over copper, not carrier.
4. A 403 card is an isolator to allow Music on Hold to be used on more then one line (otherwise you get cross talk). I'm not sure if it could be used in a 551, but I believe so.
A 551 has 18 pin card slots. Some cards (414 manual ring down for example) looked like they were the same size as a 400 but were actually 20 pin.
Sam
Phonut:
Have you read BSP 518-215-400? That's where the answers are.
You can Google it.
Arthur -
Thanks for including the link to the BSP. It does indeed answer every question.
Sam
I looked at the 518-215-407 BSP. That's what raised some of the above questions. I have not looked at the xxx-400 BSP in its entirety but I did not see anything about a 403 KTU even when I Googled it so thanks for explaining that to me.
I have a couple follow-up questions:
1. Do you just insert a Music-on-hold card in one of the line card slots and you get MOH? Say you inserted it in line 4's slot: do you get MOH on the other three lines if you push the Hold button, or do you push line 4 to get MOH?
2. BSP xxxxx-407 says a maximum of 5 stations can be wired directly to KSU (and I understand that.) "If more are required, use loop through terminations or provide destribution facilities." That I don't understand. Is the connector block in the KSU a different type than that a normal 66? It appears to me in my limited knowledge that the connector block in the KSU is a special 66 block. Is that true?
1. The 451 KTu is the MOH unit, but it cannot be used in a 551 KSU. It does not work the way you imagine.
2. The loop-thru method means that the 5 rows of output pins can be used to terminate one double-ended (female/female) station cable, with the wires punched down using the "other end" of the punch-down tool. (the blade can be reversed in the handle to allow a wire to be terminated and then head off to other points, without cutting it off). It assumes that one, double-ended cable can be run to two (exactly the right) locations in a wiring plan, with no slack, and look like someone sane did it. This method assumes ten stations, two at a time, at the opposite ends of 5 cables.
This suggested cabling method ranks among what is one of the stupidest suggestions ever found in a Bell System practice. Don't even think of doing it that way. Use one 25-pair stub cable, cut down in the KSU, and terminate it on a 66B25 block, outside the KSU. Then terminate your station cables, two per block, on 66M50 blocks. Run cross-connections from the feed block to the station blocks. That will allow you to energize ten stations.
The shoebox cabinet is just too small to do any neat wiring work inside, unless you are just using it for a demo, feeding one or two phones.
Thank you Arthur. I will try that. I did get the KSU with two cables already attached just so I could quickly find out if it worked. I then had another cable punched down which I now regret. My goal was to have a plug 'n' play KSU, that if I so desired, remove it and hang another KSU. I have a 66 connecting block with about 5 male amphenol plugs attached to it. Do you have any idea what these could be used for?
Pretty much need a picture to determine what you have.
A 403 card was an ITT product, not WE. As I recall, you fed music in from a source (tape deck, fm radio, etc) in on pins 3&18 and looped it (unless it was already looped) to all the lines you wanted MOH on. Some line cards (Sanbar 4200 maybe?) did not need a 403. Others did. Pins 3&18 often came with A Battery wired to it (401, 415 and other cards required it). If it was there you had to remove it.
I'm really digging deep for this stuff, so forgive any errors.
Sam
Phonenut:
If you're using real CO lines (i.e. copper from local phone company) and want your KSU to work for normal, everyday use, a 400D line card should work. They are cheap. For more modern uses (i.e. dial tone from your cable company, Vonage), I would suggest a Western Electric 400G or 400H which are also inexpensive. A 400H will even work with a MagicJack I discovered. You could also use the a San/Bar 4000F or higher, which I believe is roughly equivalent to the WE 400G-H series line cards.
Here's a link that lists some of the 400+ line cards and their uses.
Western Electric 1A2 key telephone reference.
WE never made a 403 KTU. That would have been the 4" card version of the 1A1 203 KTU, which was some sort of tie-line, ISTR.
ITT, as Sam has recalled, made a MOH adapter that was numbered 403. Is that what you have?
The SanBar 4200 CO card is the best solution, requiring just a few wires to be strapped in the KSU, and an external source to provide the tunes.
I'd like to return to the 415 card, the hot line or tie line or automatic ringdown, etc. I have read the BSP and you are correct whoever said you need another 415 card at the far end according to BSP. However, that seems crazy to me. Does that mean you have another KSU with a 415 card there or is the card mounted by the other phone's jack? It does not make sense to me. I have an automatic ringdown unit, not a 1A2 system, that you plug one phone in one jack and the other phone in the other jack. It seems to me that if you had a 415 card in slot 4, when you pressed line 4, some designated phone would ring. What am I missing here?
So, Mark, I have looked at this reference before, but can't help wonder, if there are 35+ line cards, but a 551C can only use 4 of them?
551c was the small domestic key configuration and thus somewhat limited in what it could support. I always installed the 584c panels in 16c rack mount apparatus or the rolling floor racks. You could have many 584c panels in a large installation.
A tie-line is a full-time private connection, accessed either by inserting a TRK cord into a tie-line jack (in the case of a manual PBX) or by dialing an access code (in the case of a dial PBX) or by selecting a key on a key set (in the case of a key system). It signals an equivalent unit at the distant end, which is assumed to be at another premises. The answer to your question is that you need a 415 at "this" end and one at "that" end. The cards are plugged into two separate KSU's, one at each of the premises that are tied together over a distance of several to many miles.
Key system-based tie-lines can be automatic, or manual. The 461A KTU is a manual unit. The 415 is an automatic one. The circuits at both ends need to be electrically equivalent, in most cases. There are situations where one end would be automatic (immediate ring-down upon going off-hook) and manual ring-down at the other end, but those cases were extremely rare.
"(I) can't help wonder, if there are 35+ line cards, but a 551C can only use 4 of them?"
Because the 35+ types are used for 35+ different jobs. It would be highly unlikely that any installation would require one (or more) of every type of KTU. Generally, they would be mostly CO line cards, with a few manual intercom (401) cards. It was a rare occasion to find a tie-line card, because the mileage charges between subscribers was prohibitive. They were installed for customers who "did the math" and figured out that the toll charges for dial-up calls between their premises were more than the cost of a private, non-dialed, connection.
In later years, ISTR in the 1980's, the BOC's offered an automatic ringdown circuit that was based entirely on central office equipment, with just a T&R appearance at each end. I don't remember the exact USOC, but I will do a little research and let you know.
Technically, a tie-line connects PBX's, and a private line connects stations or key systems. I just wanted to make that distinction, in case someone wanted to argue that point.
Re: 403 card. This card has no identifying labels other than 403. I agree it is not WE, but not sure it is ITT either.
Regarding tie line: Arthur, I can see what you're saying about a 415 card for Commissioner Gordon to contact Batman on his Batphone. But what if Batman wanted to have a dedicated key on any of his 2565 phones that he could just pick up and ring Alfred in the butler's pantry? Surely WE would have made some type of card to address this?!?!
You can put two similar, automatic ring-down private line KTU's (such as the 415A) in the same KSU and pretend that they are separated by a distance. Just tie their supposed "line out" tips and rings together at your MDF. It would probably work better if you had a larger KSU than a shoebox, since the arrangement would use up two slots.
You could use one 418A KTU. which was designed for a short-range DC (rather than generator) controlled private line, but it won't fit into a standard 18-pin connector. It takes a 20-pin connector, found in special KSU apparatus.
In later electronic key systems, you can program that feature in software. It's called, variously, hot-line, boss/secretary, or other terms.
Bill:
I believe you can use more than four basic types cards in a 551 KSU. However, some cards may require a change in the wiring/connections in the KSU so that the right voltage goes to the right pins on specialty 1A2 line cards. Generally, if you were a customer who needed such special features, Ma Bell would have installed something other than a basic 551 shoebox KSU at your premises.
Thanks,Arthur, but without sounding too stupid, what is an MDF?
https://en.wikipedia.org/wiki/Main_distribution_frameThe backboard that is centrally located, equipped with terminals where all your key system, station, and central office cables and connections appear. It's where you make the cross-connections that bring dial tone to the equipment, and features to the stations.
https://sundance-communications.com/forum/ubbthreads.php/topics/568832/Photo%27s_of_large_1A2_system_an#Post568832
Here is a posting from this very 1A2 sub-forum from earlier today. It is from my friend Phil who has a huge PBX and key system collection. Click the link that he provided and you will see a large key system MDF.
And thanks, Phil, for your insight. While we are talking about this, I know the 551 has only 4 slots for cards while the 256x has 5 keys. Is the fifth key for a separately wired intercom such as the Melco or Tone Commander? Or what else could the fifth key be used for and how would it be wired?
Arthur Bloom stated earlier: "This suggested cabling method ranks among what is one of the stupidest suggestions ever found in a Bell System practice. Don't even think of doing it that way. Use one 25-pair stub cable, cut down in the KSU, and terminate it on a 66B25 block, outside the KSU. Then terminate your station cables, two per block, on 66M50 blocks. Run cross-connections from the feed block to the station blocks. That will allow you to energize ten stations."
I found some of my connecting blocks: Have 4 Siemon Co. S66 M and this is the one I said had 4 Amphenol male plugs wired to each of the 4 columns. Is this useable in what you described above? Also have a WE 700A-66-B1-25 jack where the 4th column is wired to a female Amphenol connector. Is this anything like you described above? Sorry to say, all these 66 connecting blocks look alike to me and I don't understand the nuances between them.
Those blocks are made for specific uses. There are all sorts of subscriber and central office applications that use 25-pair connectorized cables. They are not generally used in 1A2 installations. The blocks to use to terminate key equipment are 66B25, and the blocks for station cables are 66M50.
It's just the way it is that there are 5 line keys on a 565 set and 4 slots in a 551 KSU. I think you're trying to read too much into all this. These systems are made for growth, and the number of keys versus the number of slots is not correlative. There are 3-line sets (54x series) 5-line sets (56x series) and 9-line sets (83x series.) There are Call Directors that come with 5, 11, 17, and 29-line capacities. There are 584C panels that provide 13 slots per panel, and they can be multipled infinitely.
If a subscriber needed a couple of lines and a manual intercom, a shoebox was prescribed. The original 1A1 systems (301-type KSU's) had line circuits for 4 CO lines, and had a dial selective intercom (207C) unit factory-installed. So in that case, the phones "matched" the KSU, but it was just a coincidence.
When 1A2 was introduced, and a shoebox was too small, then the installer would put in a 501, which has room for a 207C, and a 216A. Some 501 types came with a prewired power unit, and some didn't.
In later years, packaged intercoms and other packaged devices like amplifiers, service observation units, and special relay assemblies were designed to fit between the 7" space between the horizontal bars of a 501 and other cabinets like the 16C.
I plan on using 2 415s KTUs in the same KSU (620a modular panel). - What is the difference between a 415A and 415B?
- Can I use one of each in the same KSU?
- Lastly, I can't find the BSP that gives the specifics on it; I found many references to it in other BSPs. Any idea of the actual one for it?
Thanks all!
B. 415-Type KTU (Automatic, DC Signaling, Private
Line Circuit) (
2.23 The 415A (MD) and B KTUs are 4-inch,
18-contact KTU s for connecting stations in
the system to a private line terminated at a distant
station. Another 415-type KTU, or other private
line KTU which will respond to a de signal, is
required at the distant end. The 415-type can be
installed in any of the CO/PBX jacks of the 680B
Qnly. Do not use a 416-~ype in the 680B
KSU if music-on-hold is· furnished. The
580A does not have "A" battery and ground wired
to these jacks and, therefore, will not accept the
circuit. Additional information on the 415-type
KTU can be found in Section 518-215-400 and
CD/SD-69559-01.
Google ITT 415 KTU. It has a complete KSP (ITT's version of the BSP). See the above paragraph (BSP 518-215-400 for info on the WECO version.
It would appear that the 415B is just a later version, perhaps created to eliminate the problem I mentioned earlier with signaling over carrier. I don't know if the "A" and "B" versions are compatible. Probably, but......
Sam
Thank you all for your your insight on this!
One other important point about 415 cards and tie lines:
Before Caller ID when your phone rang you had no idea who was calling. Unless you had a tie line/hot line. Then you knew exactly who was calling.
On Wall Street traders "turrets" (giant key phones) almost all the circuits were hot lines. This way when the phone rang the trader could decide if he wanted to put his current call on hold or ignore the incoming call.
Same goes for corporations. Was the factory/headquarters/whoever calling or was it.......someone?
Notice the name: HOT line. Someone important. Someone who was willing to pay the freight for mileage charges so you knew who was calling.
Sam
Yes, exactly like Bruce Wayne!!
Earlier Arthur stated, "This suggested cabling method ranks among what is one of the stupidest suggestions ever found in a Bell System practice. Don't even think of doing it that way. Use one 25-pair stub cable, cut down in the KSU, and terminate it on a 66B25 block, outside the KSU. Then terminate your station cables, two per block, on 66M50 blocks. Run cross-connections from the feed block to the station blocks. That will allow you to energize ten stations."
Arthur, if you can indulge me one more time,(I have 2 empty columns on my KSU) can you tell me why I can't just hook my KSU to two 66M50 blocks and then punch down 3 cables to each one? I guess I don't understand the need for the 66B25 and what role it actually plays. It would seem that my method would at least give me 6 additional stations which is probably all I need whereas what you described would give me 10.
Bill -
Yes, you're correct. You could feed 6 stations off 3 M1-50 blocks (using bridging clips). Arthur's suggestion of the 66B4-25 block is the method we all liked best, because it gave you the most flexibility. It was always my experience that when you allowed for 6 stations, you somehow always needed 7, or maybe 8.
We often put 2, 66B4-25 blocks in, side-by-side, with the feed pins touching. Then we would loop one side and punch down the other. Allowing us 10 pins (20 stations!) with only one feed cable. No one ever went broke assuming extra stations would someday be installed.
Sam
Sam, if I may ask you one more question: I know what the A, B, C, and M designations stand for, but what is the difference between a -25 and -50 block? Thay both have 66 pins per column. The only difference I can see is the -25 is electrically connected between columns 1 and 2, and 3 and 4 but the first two columns are electrically isolated from the last two. In the -50, all the columns are electrically connected.
Yup, the -50 block is commonly referred to as a "Split-Block". You can terminate cables (a single 25-pair, or 6 4-pair, or 8 3-pair) on the outer column of either side. Then you can run jumpers to the connected columns and have each outside cable independent, or you can run your jumper to just one column and use a bridge clip to connect to both cables on the outside columns.
66 blocks do not have 66 rows. They have 50 rows, generally. Sometimes fewer, like 32 for a 16-pair cable, or 12, for a 6-pair cable.
66B25 and 66B50 are the last iterations of the blocks that are bigger. (More space between rows than the "M" [mini] blocks do, so they are physically taller, and take more room on an MDF.)
M blocks come in 25-pair versions, (4 pins across each row, all connected) and 50-pair versions (two sets of 2 pins in each row, left side insulated from the right side.)
My suggestion to remote the outputs from the shoebox to an out-board block has little to do with electricity, and more to do with physical convenience and trouble avoidance. It was said to rebut the notion of trying to cram 10 cables (wired using the loop-through method) into a shoebox.
After having wired approx 10K key sets in my lifetime, my method is to provide a source block (generally a 66B25, for ease of counting and 5 useful outputs) and to provide a 66M-50 split block for every 2 key sets. Then, cross-connections are run to take the features from the source block, and assign them to the key sets.
If you do that once, you have accommodated 10 sets. You can do it 4 more times, from a shoebox internal block, and energize up to a total of 50 key sets. More than a sane collector would want hooked up at one time. I, of course, am not quite sane, and have 20 or so key sets hooked up right at the moment.
I hear you. I still would like a method to isolate my KSU except for the CO lines so if I wanted to change it to another KSU, I could simply unplug the Amphenol connectors and do it. But that is down the road, just trying to get all the wires run and all the stations hooked up. Thanks to all for your help.
There is no reason why you couldn't have a 25 pair feed tail with a female amp connector coming from the KSU to the first 25 pair block, such as 66A25 or 66B25 and have, as the first connection to the block a 25 pair cable terminated to a male amp connector. This will facilitate being able to quickly change out the KSU for another. You can also use M blocks with a built in 25 pair amp connector on it, but that kind of makes an additional point of connection that is unnecessary. The method Arthur described is an excellent method of building a good, serviceable key system cross connect field.
Rcaman