sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems KTU issues

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.