Thanks to everyone on the forum, my 1a2 system is working perfectly, but now I have one more question. At my office (Noretl/Norstar System) I am used to dialing 9 for an outside line. It would be nice if I could configure my 1a2 system to require 9 for an outside line ( I know this is conuter-intuitive- pushing the outside line key gives me an outside line)

If I want to configure it such that I need to dial 9 for an outside line, what would be the easiest/cheapest way to do that ?

A Centrex line is the only thing I can think of and not cheap. Or put it behind an electronic key system.

Wow. Why? You could insert a key system with analog trunks between your 1A2 and the central office; a Panasonic, Partner, or any key system with trunks and analog stations would do the trick.

I've seen basic Pana 308/616 systems for sub $100 on eBay.

Carl

This was actually something we did years ago for someone. Most of the house was wired with 25 pair and had 1A2 sets, but some locations only had 6 pair. (They were two line 500 type sets - I forget the number - 502 maybe?, but they only picked up the two dial tone lines.) Rewiring those locations was problematic and would have caused much expense in the house (a very, very fancy place.)

We rewired those sets to the dial Intercom only and then rewired the DICM so that when you dialed "9" you closed a relay and picked up line 1. Dialing "8" picked up line 2.

As I recall, we used the latching contact in the ICM to hold a 17B (DPDT) in place.

Sam

Sam you never cease to amaze me. You and Arthur must have done about everything with 1A2 that could be done.

I did the same thing that Sam mentioned, but I used 1A1 relays and other misc. 6A intercom apparatus to make it happen. Those things are so easy to wire however you wish. My reason for doing this setup was because I had a mix of single line and key sets in my house. It wasn't graceful to operate, in fact there really wasn't anything that could be done except to answer or place outside calls (no call transfer, etc.) but it was really more of a hobby setup than anything.

Hint: The 237B is one of the most versatile KTUs for applications such as this since it was designed for conferencing of lines.

Ed -

You're absolutely right - about everything - but certainly about it not being graceful.

The job, as I recall was in the home of an owner of a company who's business we had interconnected. The salesman went out, saw the job and decided that it was a straight swap, because the guy had 1A2 in the house.

Not so. He had 1A, with no lamps. Some stations were wired with 25 pair and some with only 6 pair (And some with 12 pair and some with 16 pair! [which I've never seen before or since]). We were able to rewire some stations (Unobtrusively) in this mansion on Long Island's Gold Coast, but the three 6 pair stations (which had 6 pair jacks - also something almost never seen in those days!) were inaccessible.

So we came up with a creative solution - that worked. Not graceful, but it worked and I got out of the house with my skin.

Sam

Creating a situation where one user can dial an escape digit such as 9 to access a single trunk is easy. if all you want to do is to demonstrate the concept, a few relays will do it. However, if you know how a PBX actually sets up a call, and you think about how that call progresses, you will need to rethink your project.

Every extension in a PBX has a relay that identifies its line (The L relay) and another relay that cuts it off from being called when its busy (the CO relay). 100 extensions would have 100 L and 100 CO relays.

In your case, if you wish to have (only one) single-line telephone (SLT) pick up the dial intercom (DICM), dial 9 and receive outside dial tone from a pool of just one CO line, the ext will need to have some way of holding the CO line until the call is ended, and some way that allows other users to access the DICM for intercom calls while this other connection is still up.

You will also need to wire EVERY extension that wants this service with its own loop-sensing relay OR wire all the single-line sets that want this service for A-lead control.

The sequence would look like this:

EXT off hook on DICM
"A" relay operates
DICM waits for digit
EXT dials 9
One-second pulse from DICM unit operates "9" code relay
"9" code relay cuts through CO dial tone to extension
DICM unit restores to on-hook condition
"9" code relay locks up on its own windings, under control of the "A" relay
.
.
.
Call ends
Ext hangs up
"A" relay falls
"9" code relay falls


In this scenario, the other users of the DICM will be able to use it for ICM calls, but anyone of them can dial 9 and barge in, unless you equip all of them with their own Cut Off relays.

The reason you need to provide either loop sensing (with a conceptual L relay) or A-lead control for every member of the group that can dial 9 is so that when the call is finished, the system will restore and release the CO connection for the next user. This is called "supervision" and is the reason that in a real PBX, the truck circuit provides supervision via the "S" lead (Sleeve lead.) In a real PBX situation, the sleeve is grounded back through the switch train, and is under control of the trunk loop current, so that when a trunk call is retired, the sleeve ground is removed and all the parts restore for the next call.

So...at a minimum, to demonstrate the concept, you need one SLT wired for A-lead control, and two relays, one with one set of transfer contacts and one with a single transfer contact.

If you want to use a pick-up on a key set for the DICM, you could use the A-lead control for the key set, but would still need two relays per "EXT" that have access to the demonstration circuit.

If the trunk you want to use also appears on a button of the keysets, you would need to ground the A-lead of the associated line card, so that the line lamp on all the sets with that line would come on to indicate that the line is BUSY. Any user with that line on his set could barge in, BUT you could add a third relay (per trunk) with two transfer contacts that would exclude the T&R of the truck from the key system, so that the dial tone would be cut off from access on those key set buttons.

It would also be advisable to swap the SIG output supply of the DICM unit so that it sends a GRD pulse instead of a BAT pulse. The code relay would then lock up on GRD rather than BAT and the same GRD could be used for grounding the A lead of the line card.

If you can't find a pair of 17B KTU's to use as the relays, and you don't mind using COTS equipment (Commercial Off The Shelf) use two of these

Arthur -

As always, succinct and impressive.

Sam

Sam, thank you. Modesty precludes me from agreeing with you.

I've had a 1A2 system at home for many years. It's been modified with a circuit replacing the 400E card so non-A lead phones can be used and provide off hook status. Hold is kind of reversed, line 5 is converted to a momentary pushbutton and a couple of leads are moved. It has a Melco intercom, pressing 9 gets the CO line. Previous circuits had a line isolation transformer and used A battery, but I no longer use the original Elgin power supply. It's quite basic - pressing 9 sends a momentary +24 to the circuit. I'm going to attempt to insert a link to the schematic, sorry if it doesn't work. I'm not sure if I should chose "Insert an image' or 'Create a link to a webpage' - - The 'Dial 9 acess' link appears to work.

Dial 9 access

Thanks for posting the actual file! Please let me know how you did that.

Saved your picture to my computer, uploaded it to imgur, then posted the link

Ok - at some point I'll post the line status and hold schematics. I now refer to the former A lead as the H lead, + present when pressing the hold key while going on hook. The line in use indicator is a basic opto-isolator circuit, hold is 2 relays. From what I read about 1A1 systems the hold circuit may be based on that, also very basic. I now use the doorbell transformer to power the lamps. It's 18vac, so there's 2 diodes in series to drop it a little. Yes the lamps will dim when both the CO and intercom are in use. There is no longer a bathroom phone, but do like being able to pickup in the garage and cordless phone. I don't have my basic caveman cellphone on me when I'm home. I much prefer talking on tip & ring.

I just read AT&T is selling out all landline facilities in my state to another company, Frontier. I hate to do it but looking at Frontier's rates I may need to finally retire my analog CO line and consider voip, but would want an analog adapter for the key system. Quite a few choices available, will need to do some research.

Tiny topic detour...I never understood why SBC wanted to buy SNET. The northeast was primarily Verizon territory and that meant that SBC was isolated. That didn't change when SBC bought out AT&T.

In terms of ATAs, I use the Cisco 186. Awesome little device that lets you customize just about everything, including the ring cadence and the region of the ringback and other tones. My one problem with it is that it puts the caller ID name in quotes.

Like this:

"Cell Phone Wa"
1-360-555-1234

If you are considering an ATA the Cisco model does provide two ports, so two CO lines on the KSU. Also, check out CallCentric for VoIP service. I pay just shy of $15/mo for my local Oak Harbor, Washington DID # and 500 minutes to any North American number.

Thanks for the VoIP/ATA information. When you mention the caller ID is in quotes - that's how it's displayed on a Caller ID built into a phone or standalone unit?

Even if I didn't have the CO line I'd have the key system. Now that school is out for the year someone is here at times so the intercom is used as a typical intercom again. Also use it to control other circuits for lights. Although I don't use the remote function much now, I'm able to call the answering system via the intercom and access it remotely. There's a lot that can be done with the Melco intercom. I may have one more if it fails, otherwise I may need to convert a couple more line keys for other functions.

The VoIP using an ATA is all new to me, sort of. Had a Magic Jack several years ago connected to line 2 of the key system (formerly a CO line for voice and internet dial-up). It actually wasn't bad at all - at the time I had DSL and several others could be doing things online so the audio could get choppy. With the current cable internet and it's usage that's not a concern. Whatever I get will be used with the 1A2 system. The only ringer load will be an electronic phone. That phone's tone ringer is fed into a paging amplifier.

The caller ID name shows in quotations no matter what device is receiving the data. Right now, it's a Partner 34D set on my Partner ACS system.

On Magic Jack you won't get the CO line disconnect signal that will release a held line on your KSU. That's what sucks about it.

Disconnect supervision would be good.

I'm going to attempt to post the CO off hook and hold circuit using Jeff M's method. At the time I didn't have an electronic template for Power Point so the schematic has components drawn from shapes.

This allows using any analog phone on the system. I have a couple 2564 keyfields in a small wood enclosure with a modern speakerphone on top. When the line is idle the 48v turns the optoisolator on, sending a ground to the transistor keeping it off. When a phone is off hook there's not enough voltage to activate the optoisolator. That allows the transistor to activate via the 47k resistor as there's no longer a ground through the 390 ohm resistor. The CO seems to reverse T&R during the ring cycle - the lamp will remain on between ring cycles. I could have made a bridge rectifier, but the answering system will pick up on the second ring.

(Thanks Jeff, using preview it appears the image will display)