I've read on this forum that the 18D KTU will provide A Lead control when connected in front of the 400-type KTU. I need 2 for my home application (I have one already). These hardly ever come up on eBay; I see relays out there now, the...

2A
5A
6B
17B

Can any of these be used (I didn't locate info in any BSPs on these)? I only need the function to show line in use, not removing from hold if this makes a difference.

Thanks for any guidance!

Jim

Have you tried checking here: https://www.telephonecollectors.info/

The 18D is the one to use. I never had any, but I did use 6Bs. They gave an off=hook indication, but as I recall they wouldn't break hold.

Sandman used to sell A- Lead control stuff as did...Crest? Maybe.

The 2A was as i recall for T&R for an ICM (I could be very wrong - it's been a l o o o n g time.

The 17B was a DPDT relay.

I'll email you PDFs of the relays that I have.

Sam

I have a few synapses in my brain jumping up and down saying ChrisRR had some A lead control boards some years ago, and I think had some to spare (at the time). He had board designs and such I think, and they're /probably/ easy to build. Not sure though..

Hi Sam, I also be interested in your PDF of Relays.

Get me an email address and I'll send you PDFs. Unfortunately, the only ones I still have are the 6B, the 15D and the 17B.

Sam

Sam, I just sent you a pm with me email..

Hi Sam, Thanks for providing the diagrams for the KTUs (I traced down the BSP # and found the complete documents). Luckily, there are 6Bs on ebay, and I just ordered them. Can't wait to test and compare their operation to the 18D I have on another line. Since I'm only looking for the line-in-use indicated via A-Lead, the 6B may be the ticket! I'll post my results. Thanks for helping. Jim

Hey Jim,

Another option is to use a Radio Shack Duofone Telephone Multi-Line Controller item # 43-233, they come up on Ebay time to time. But the 6B KTU can be more of a nicer installation do to its size. .

EBay

https://www.ebay.com/itm/184995740674

The 6B KTU was fairly common and might be easier to find. This is the purpose for which it was manufactured.