sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 400D KTU Issue 14/15 schematic needed

Hello all. I have the schematics for the older 400D issue 8 series cards, but the issue 15 card (~1973 era) is sufficently different. I'm using a 551A KSU. I'm in the process of interfacing a modern Panasonic FAX/Phone-answer machine and having some ringing/auto disconnect issues when used with Magic Jack. (The MJ ring voltage & talk loop current are OK). I need to modify the 400D card ring detector - thus I need the schematic for the Issue 15 series card. I've searched the usual with no success, so I hope someone here has the info. TIA.
George

I've got the "Key Systems Service Manual (Volume II)", dated October 1978. All it has is the "condensed functional schematic" for the 400D, with no indication of the issue #. I don't think it'll help you, but you're welcome to a copy if you like.

I'm not sure what it is you're trying to do, but would a different 400 card (ITT 400E, Sanbar 4000F, WE 400G/H) work any better?

Sam

As Sam said, the 1A2 service manuals and all related BSP's show a condensed schematic. For the real nitty-gritty (in all its hand-drawn glory), I think what you want is SD-69513, "Key Telephone System No. 1A2 CO or PBX Line Circuit."

Direct links to manuals are discouraged in this forum, however this isn't really a manual, but rather a [historic] schematic, so here goes:

link to the past when phones were reliable

Good luck to you, and welcome to the forum!

Jim
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Speaking from a secure undisclosed location.

Something like that is ok Jim. Nice find.

Good catch, Jim!


Sam

Arthur's link is better - it also has the "CD" pages, a.k.a. "Circuit Description." They give an extremely detailed description of the operation of the card. I didn't know how much I didn't know until I read that...

The site at the link I gave may have the CD as well, but I can never actually find anything on that site. I'm not complaining (never look a gift horse etc.), but that tree thingie they have in the left hand pane is, well, a pain. Go with Arthur's link instead.

Jim
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Speaking from a secure undisclosed location.

George, I'm on Shelter Island. If you want to chat about 1A2 or even older stuff, give me a shout.

I'm slowly building the Shelter Island Museum of Telephony, which will feature a 200-line WE 701B PBX (Step-by-step) and a bunch of 1A2 circuitry.

631-749-0100

C*NET 749-0100

The Collectors\' Network

Hello Guys. You look like a nice bunch of fellows (OM's, myself included)with a lot of knowledge. Tnx for the link(s) to the information, etc. Much appreciated.

All has been happy here in 1A2 phone land for 40+ years until I decided to change over to a Magic Jack and do away with CableVision/Optonline $30/month service - Why? - that's a story for another time. It had to do with vacation service & call forwarding. So to the problem - I know the 400D cards detect ring voltage to gnd, and the MJ ring voltage is line to line. Thus I want to modify the 400D by adding a simple Optoisolator ring detector to "fool" the card. This may be a non problem since I've found out the 400G cards will detect line to line ring voltage. I've ordered 2 off ebay from tigger696998 at a reasonable $5 each. This stuff is now considered "vintage collectable" ha ha. It's been bullet proof for me all this time and you can "see" and repair the components. Anyway, the old documentation I have is for the 400D series/issue 2 & 8 and the issue 14/15 cards are a different in schematic & layout even though they function the same. I was thinking along the lines of detecting the ring (optoisolator, series cap & resistor) and causing a transistor to short out the 327 line relay contact or whatever needs to wake up the card. Any other suggestions how to do this? I don't need to reinvent the wheel. The "G" cards may do it. Also, does anyone know the equivalent or specs for the zeners & diodes used on the cards?
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About my 1A2 system. I've had a 1A2/551A KSU (shoebox)system in use here in my home since the late 60's, some 40+ years. No problems. I built the system fitted out with 2, 400D line cards (line 1&2) a 401A intercom card (line 3) with the 207C rotary stepper and 3, 216A stackup relays for a 36 sta dial intercom/controller. Common talk, independent station sig to gnd to the little buzzers in each phone or to control something else with the ~1 sec gnd connection. Dial "0" and all phones buzz. The infamous 247B TT decoder got added later when they became available. I have 8 keyset phones around the house, originally rotary 565HK's (changed out/converted some to 2565HK's later) plus some single line phones (garage, bkyard, shed, etc) on the dial intercom system so they can dial 9 for connect to line 1 for outside line or call pickup. Ring generator pwr supply is a 20B2, upgraded from a 3V55 (subcycle ?) - the one with the 3 big toroids - unknown date, but it's veeeery old, older than me and dirt, ha ha. Still hums when I plug it in. I also homebrewed in an audio amplifier & relays to use PTT (line 5) to talk/listen thru a spkr to the front door or the bkyard spkr to call/listen to the kids for lunch, etc. All grown up and moved out now. A 2565 has line 1 Exclusion pull up key in my little office. To complete the description, line 4 connects to a 146/448 MHz FM Ham radio to monitor a radio repeater with PTT (Line 5) to transmit. I've added non-std phones (wireless & answer machine) by adding a small reed relay for the A & A1 cntl lines, with no hold functions. I wired all the keyset red hold 51A (LH) lamps to the 10 VAC with a series diode (reduced brightness & extend life to 20+ yrs) to serve as night lights and tell the me system is powered. If I get really ambitious, I may make these lamps wink if there is an answer machine message. No time for this - I'm retired, ya know!

I hope this hasn't been too long a description to digest. I've probably forgotten a lot about what I did a long time ago, but I kept a folder with BSP documentation I've collected over the years as/wherever I found it along with various surplus phone devices. Any other questions, please ask.

Again nice to hook up with you guys.

George

George -

Sounds like a nice setup! I know what you mean about not having any time because you're retired (I went out this year and I've never been so busy). I would go with the 'G' card if it does what you need (but then, I'm lazy). I seem to remember complaints with the G & H cards, but that the Sanbar 4000F or the ITT 400E would work better. Either way. If you need any cards many of the folks here can help you out. And if you want to add a little more 'functionality' to your system I just found a box of 17A/B & 6B/C KTUs. Oh, and welcome to the board!

Arthur -

Excellent site! Thanks!

Sam