atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Does anyone have an ITT 601A KSU in use?

Station Specialties,

I said the CO line cards do not use the AG AB for talk voltage. The circuit works with Central Office supplied voltage. The BG and BB are used on the CO cards for relay operation and A lead control. In this case, the ITT 601 has NO BG and BB. The AG and AB is all that is supplied for both relay control and intercom talk battery.

If Matt1964 wants to use the AG AB for talk battery, he needs to filter it better than it is.

Rcaman

Which I just got the parts for, will update soon. Thanks RCA!

the b battery runs the lamps. from 10-24. The more sets you have to wire the B battery to 24 on the lamps is used based on dimming of lights based on the total number of sets off the power supply.

If you only have 5 or 7 sers then 18 on the b batt is correct..

If you are trying to connect a melco intercom forget how you wired the sets.

Forget what ever prints you have.

The melco has two inputs. One for A battery and one for singnal b battery...

The latch contact makes the switchhook contact in this unit.. If you wire it right you will hear the relay in the intercom unit click. The relay is now looking for audible volatage contacts.

If its a TT intercom you will hear the latch .. It has now made a second connection looking for B battery audible to ring or buzz the station.

OK....I have only been at this for 40 years, so I know I still have a lot to learn. However, my days at Bell Telephone taught me that if I hook up BG and BB to lamps, I'll have a lot of burned out bulbs as ALL line key bulbs are 10 volt in 99% of all 1A2 sets. BG and BB were designed as an unfiltered voltage source for operating relays. The AG and AB were designed as a fairly well filtered voltage source for talk battery for intercoms, etc. RG and RB were used for common ringing and SG SB for intercom buzzers.

I did not see any mention of a Melco intercom unit in any of Matt1964's posts.

Rcaman

The ITT 601 was even more flexible than a Weco 551.

601 had it's own ring generator buit in. The 551 was a plug in add on type transformer that had to be wired up to inputs on the shoebox 66 type panel.

I worked on a lot of weco key systems. The ITT was better. It didnt blow fuses as easy as a weco. When it did blow a fuse it usually fxxck up the line card unlike the Weco.

RCAMan:

The intercom unit was mentioned and illustrated in This thread. Scroll down and you'll see.

It looks to me to be a Teltone intercom, but the brand really wouldn't matter, nor be an issue in this case since it's not even connected yet.

If you worked on it for ten years every day it's enough to last you a lifetime. One can install it. Then there those who fix it.

When it doesn't work and to keep it going from bad keypads to dirty button contacts to water on the foor in a amp connector and a host of other basic electricity issues.

These old phone system are basic electricity.

Patients with 1a2 is a virtue. The best guys who work on this stuff are now 80 years old.

Let's move on to Tesla.


The best thing about 1a2 was that if you could fix the worst problem in a couple of hours the General Manager of AT&T needed you.

Matt, I think along with your VOM, you may need a BS detector.

If you need any more 1A2 advice, and don't necessarily want to be publicly abused and confused, just give me a call. You have my number.

RCAMan - sorry, still have hum. I'm giving up on this... I know the intercom card for this KSU presents a clean talk path, so I'm off to pursue my options there.

Arthur -

I hear ya.

Thanks
Matt

Thanks John! Gotta say I'm having just as much fun - glad to hear you guys are getting a kick out of it as well. This stuff just fascinates me for some reason.... looking at a bunch of wires and 66 blocks, wondering how in the h*** is this all going to come together, and then suddenly (in my case with a great deal of help) ... the light comes on. VERY satisfying. I think this is the first hobby I've had in years that I truly enjoy. Anyway, thanks for the kudos!

- Matt