atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems ITT 501C Intercom

Hello all -

I've been browsing the forum, but can't seem to find exactly what I'm looking for. I have an ITT 501 C Shoebox KSU, (I think it's a 501C, gray cover with an ITT logo in the lower right corner).

So far I've hooked up 2 keysets, and am having lots of fun with the system in general.

The KSU came with a 183981-101-PAK card, which I believe is for intercom functionality between the keysets. I have a number of 10v buzzers, and want to have a go at getting the intercom functionality online.

Problem is, I don't know where to start. Can anyone help? I've seen some posts about what leads to conenct the buzzers to in the keysets, but after that, things get a bit fuzzy. I've also reviewed the schematics over at kadiac.org; but I'm still lost. Even assuming I knew how to wire the stuff up, I'd still be helpless as I don't even know how to use it.... (i.e. what buttons to push to signal another keyset).

Any help is appreciated!

Thanks
Matt

You take the locking screw out of the buttons you want to use for signaling and use the A leads for your signal lead. You have to decide who signals who and wire accordingly. Have fun. Buttons and buzzer Oh my.

Matt:

What you have is an ITT 601A KSU, one of the last 1A2 systems made by ITT. The card that you have is a 9-station rotary dial intercom unit. It may have a daughter board attached on it to adapt it for touch-tone use.

This card goes in the bottom slot only, in fact that should be the only slot that will hold it. Near this slot on the 66 block, you'll see rows of clips labeled "T and R" toward the very bottom. There won't be any dial tone on them, just talk battery. You will also see the next rows labeled "LG and L". These are for the line button's lamp. There are no A lead connections required.

In that same area of the block, you'll see ten individual clips numbered 0-9. Note that the numbers are stamped in between the rows, not along the block's fanning strip. You'll connect each buzzer each one of these digits. The other buzzer lead will connect to signal ground (any unused LG or A1 terminal will do). ITT sets use the orange/yellow pair for the buzzer. Western Electric sets use the yellow/green or yellow/orange pair. It really doesn't matter which pair you use.

Operation of the intercom is to simply go off-hook and dial the single digit desired. You won't hear any feedback at all and the intercom path isn't private. The buzzers receive a one-second burst of 10 volts AC when dialed, however they can be repeatedly dialed (or other digits) without hanging up the handset.

If you simply want "button and buzzer" signaling, you will need to have a 401A or 401B card installed in any regular line card slot. From there, you'll need to wire T/R, A and LG/L as if it was a standard line. I don't see the sense in doing this since it appears that you already have a dial intercom card.

Thanks Ed!

I'll be hooking it up tonight, will let ya know what happens. You're right about the card only fitting in one slot, and also about the daughterboard for touchtone phone... which is perfect, cause I have a mix of rotary and touch tone keysets. Can't tell ya how much I appreciate your help....!

Thanks,
Matt

I thought he wanted button and buzzers for the real 1A2 experience. :confused:

Make sure you have the correct voltage for the buzzers, the Bell System equivlent was wire from the factory for 105v intercom ringing, buzzer would click, once. I'm not sure what factory wiring would be on what you have.

I was watching a clip on YouTube of the show home improvement. He had the 1A2 phone and speaker. I never noticed before on those phones how the lights blinked. Here's the clip:

Hey all -

Well, some success, but not quite there yet. I go off hook, and press line 5. Line 5 lights, and I've got talk capability. But no buzz when pressing the number I punched down to. So, I put a voltmeter between LG and "0" (actually I tested through "9").... I'm guessing I should see around 10 volts, but.... nothing. I do hear the relays click on the intercom card though.

I noticed there are some jumpers on the intercom card, but am relectant to mess with them since I don't know what they are for.

Any ideas?

Thanks!
Matt

What are the buzzer leads cut to in the set and is that where you punched them down? Did you check both AC and DC with your meter?

On the ITT set, they are cut to Orange/Yellow. On the WE set, Yellow/Green. As for the AC/DC, yep, checked both, nothing there.

Jeff, that's very perceptive of you to notice. I often watch old movies and TV shows to see the modular cords in 1950's stories, to watch the incorrect lamp cadences, listen for incorrect ringing cadences, and to listen to the "ding-ding" coin deposit sounds on single-slot phones.

The lamps on that ITT or SC 2564 are being flashed by a non-standard piece of equipment, (probably an automotive turn signal flasher, or equivalent, or possibly even a stagehand doing it manually.)

Lamps on traditional 1A2 systems can be in one of 5 states:

Line idle, lamp OFF.

Line in use, lamp STEADY.

On an incoming call, the lamps FLASH at 60 IPM. A half-second on and a half-second off.

When the line is on hold, the lamps WINK at 120 IPM.

When the line is on "I-HOLD" (pronounced EYE-HOLD) the lamps FLUTTER. (Flutter is provided by a 408-series or 430-series KTU, and sets are wired especially for the I-HOLD feature.)

The lamps on the TV clip are doing "none of the above." Good catch!