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Melco KT-37 Intercom 2

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dialanumber

Technical User
Dec 17, 2012
10
Anyone familiar with installation of a Melco KT-37? I've been given the job of figuring out how this dinosaur works and I don't have much 1A2 experience. I'm connecting it to a Western Electric 551C KSU. I've just about got the KSU and phones figured out but I'm having trouble with the Melco. Any help is appeciated. The installation instructions on the unit are hard to read and I cna't find any instructions on the web.
 
The wiring diagram should be on the side of the unit

OLD ROLMEN WORKING ON NORTELS AND AVAYA
 
Yep it is on the side but I can't read it because most of the wording is gone.
 
Hey there, i am curious what this device is?

Wouldn't it be easier to pick up a used Norstar system (I bought one for $25 once with 10 phones) on ebay and then using the Feature 62 paging feature directly off the Norstar? Or are you doing this for a novelty? :)



****New Forum - E-Metrotel UCx****
Joseph Sus-Nortel Installer/Programmer-"JoetheUCxguy" on Youtube
 
MELCO 37 IS A 37 STATION INTERCOM FOR 1A2

OLD ROLMEN WORKING ON NORTELS AND AVAYA
 
Gordon, this was a simple intercom module for the old 1A2 key phones - it had a single common talk path for all phones, but allowed you to ring the bell or buzzer of a specific phone - the KT-37 used tone dialing and could signal 7 single digit extensions and 30 two digit extensions.

dialanumber, I couldn't find any info online for the KT-37, but did find a PDF for it's smaller brother KT-19.

goto and enter either Melco or KT-19 in their search box to download a 3 page document.

basically, the first and last 3 pairs will be the same; for the middle 19 pairs the KT-19 used 2 wires per bell/buzzer while the KT-37 used a single wire each with all the returns connected together with "AUD GRD"

These are the connections punched down on a standard 66 block - Hope this formats OK

Tip w/bl
Ring bl/wh
LB w/o
L o/w
LG w/g
PC g/q
R40 w/br
R0 br/w
R41 w/sl
NC sl/w
R42 r/bl
R43 bl/r
R44 r/o
R1 o/r
R45 r/g
R5 g/r
R46 r/br
R6 br/r
R47 r/sl
R7 sl/r
R48 bk/bl
R8 bl/bk
R49
R9
R30
R20
R31
R21
R32
R22
R33 y/bl
R23 bl/y
R34
R24
R35
R25
R36
R26
R37
R27
R38 v/bl
R28 bl/v
R39 v/o
R29 o/v
AUD GRD v/g Common Signal Voltage 20VAC or 105VAC
AUD SUP g/v 20VAC for buzzers or 105VAC for bells sent out on "R" terminals
A GRD v/br
A BAT br/v -24VDC filtered
B GRD v/sl
B BAT sl/v -24VDC unfiltered

Haven't traced all the internal wiring, but the AUD GRD is not connected internally - think of it as a big 38 position switch with AUD SUP on the common rotor, and 37 "R" outputs
 
Thanks to all for your help. I'm installing for a guy that enjoys old phones. Not have any real 1A2 experience I'm confused by some of the connections. I'm going to look at them for a while and hopefully things will make sense. Once again all your help is greatly appreciated.
 
So I'm looking for more help. Anyone know where the Melco KT-37 tip/ring connects on the Bell Systems 551c? The manual for the 551c can be found at: bellsystempractices.org/500-/...-/518-215-407-i01_1976-07-01.pdf

We are mainly using model 2564 phones and the first four line buttons from left to right correspond with the four line connections on terminals 43-50 on KSU punch down block. BUT I don't see where the fifth button that was commonly used for Intercom has the corresponding connections on KSU punch down block.

 
The Melco t&r jumpers directly to the 2564 button 5 t&r which I think is the black green pair .
 
Thanks. So if you wire directly to the phones was it typical in old days to wire the Melco to a 66B block so you can cross-connect to multiple phones? This Bell Systems 551C I'm working on is going to have up to eight phones. I plan to punch the phone jack wiring to 66M (split blocks... so I can cross-connect off a 66B from the Melco to four other blocks. Since I don't really have any 1A2 experience (the only experience I have is taking them out and putting in new systems. Now I which I would have spent more time looking at the work that was done in past). Anyone have 1A2 experience that tell me the way it was? Thanks
 
You are making me feel real old. LOL I my fis\rst job with 1A2 was in the service working in a building that had 3000+ phones and 1200+ lines through out the building. We used several 36A intercom systems for the different groups and the KT-37 was really new when I started in the civilian world. What was nice about the 1A2 was you could attach all kinds of bells and whistles to it. If you have a 564 with the full 25 pr cable to it you could set up several buzzer, bells, IC pathes, use buttons for control buttons, signaling buttons, ect. The buttons have a screw setting that will let you set then to not lock down, ie to buzz another phone, door lock, ect. Those were the days - real hands on electronic wiring paths.
 
It would be typical to terminate each station cable on a 66M150 block (one cable per side, it is a "split" block

Then you would use a 66B425 block (6 columns, 5 facing one way and 1 column to "feed" the block), and use a piece of 25 pair to connect from the KSU to this block's feed column. You might need multiple 66B425 blocks, if you have a lot of station cables, so you might place them side by side, with the feed columns facing each other, loop the feed cable to one of them and terminate on the other. This would give you 5 or 10 places to run jumpers from. Set up the feature block with CO Tip/Ring, Station T/R, A/A1, LG/L, B1/R1 for each line from the KSU.

Next to these 66B425 blocks, add one more. Terminate the cable from the KT-37 on it, so now you have a place to take the Intercom jumpers from. Use a piece of 3 pair back into the KSU to connect to the A and B battery.

It seems to be impossible to find, but "Lee's ABC's of the Telephone" published a guide to 1A2 installation, that was pretty clear on real world installation. You might also look at Bell System Practices (BSP's) on the TCI document site
 
There are a handful of "Lee's ABC's of the Telephone" books on Amazon!

jeff moss
 
Thanks to all for info. I'm kind of getting it.

"Next to these 66B425 blocks, add one more. Terminate the cable from the KT-37 on it, so now you have a place to take the Intercom jumpers from. Use a piece of 3 pair back into the KSU to connect to the A and B battery".

Questions:
I have eight extensions. So would you use two 66B425's for feed from Melco the same way that you would from the KSU? I will have to connect tip/ring to eight extensions.

A and B battery from KSU... where would you land the feed from KSU? On a dedicated 66B425 blocks that are used then to cross-connect to eight phones or something different?
 
It seems to be impossible to find, but "Lee's ABC's of the Telephone" published a guide to 1A2 installation, that was pretty clear on real world installation. You might also look at Bell System Practices (BSP's) on the TCI document site "

I've spent some time on the TCI website looking at BSP's in the past. I've been slow to understand the manuals. Any help on specific manual to look at is appreciated. There are quite a few.

Also, on the "Lee's ABC's of the Telephone"... when I type "Lee's ABC's of the Telephone" into Amazon I get:

Understanding station carrier (Lee's abc of the telephone) [Unknown Binding]
Kenneth C Nelson (Author)


I'm guessing this is not the 1A2 manual you are talking about. Any tips on finding the correct manual is appreciated. I would like to purchase.
 
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