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Posted By: morephones WECO 551B Ringers and Buzzers??? - 10/23/19 02:33 AM
Hi everyone!

I just scored my second WECO 551B KSU with a 118a Frequency generator. My question is, any way to wire up a switch or a relay at the KSU to select ether ringing with the 118a Frequency generator or just buzzers for incoming calls. If so, what modifications would I have to make to the wiring at the block. I would like to have the option to switch to ether ringing or buzzing for incoming calls.

Personally I like the sound of the buzzers when a call comes in but I do not want to have the 118a Frequency generator to go to waste...... especially since it has the rare bracket...


I would appreciate any ideas and feedback.

[Linked Image]


Thanks
Posted By: Silversam Re: WECO 551B Ringers and Buzzers??? - 10/23/19 03:46 AM
If you wire 10 or 18VAc to the RB/RG leads (where your 118 is wired) and put buzzers in the phone and connect that pair to the RG/RC leads, you'll get buzzers buzzing on incoming ring.

A relay or switch could switch the proper ringing current onto the RB/RG leads while simultaneously switching the buzzer/ringer pairs onto RG/RC.

Sam
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 10/23/19 09:23 PM
I made such switch on my 551C. But I use ringing generator with DC12V supply (from lamp/buzzer AC10V via a rectifier). So in my case it is just switching 1 contact to where the AC10V should come: to buzzers loop or to feed the ringing generator. I wired this switch to a control relay in the PBX, so I can switch buzzers to ringers and back remotely from any station by dialing the relay switch code. Alternatively it can even be controlled automatically via timer. But I do not need such.
Posted By: jeffmoss26 Re: WECO 551B Ringers and Buzzers??? - 10/23/19 11:03 PM
very cool!
Posted By: morephones Re: WECO 551B Ringers and Buzzers??? - 10/24/19 12:08 AM
hey RedBul ,

Would you mind posting some pics or a video of this setup, I would love to see it.
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 10/30/19 08:52 AM
Hi, I believe I’ve published it here couple of years ago, when I made the assembly of that KSU. But the old photos disappear somehow from the image hosting. I will make new and place the here.
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 10/30/19 09:24 AM
Here you are!

For this KSU I’ve built a small “option module” which contains 12V powered ring generator and a simple power supply for it:
[Linked Image from i.postimg.cc]

Power supply is just a diode bridge rectifier coupled with filter capacitor and a control light bulb. Because it takes power from the same 10V AC lamp source as buzzers, it is easy to switch between buzzers and ringer: simple 2 positions relay to either supply 10V AC to the ringer generator or directly to the buzzers pair to the telephone cabling:
[Linked Image from i.postimg.cc]

Also a safety 300 Ohm resistor is added in series with ringing output - it is not obligatory, but recommended to protect the ringer generator from short circuit on the ringer pair in the floor cabling.

There are no modifications done to this KSU itself with this option. The whole board is fixed using 1 screw through the standard ring generator mounting bracket hole and connected to the non-modified 66 block of 551C KSU with regular wires.

So far based on 2-3 years of using this system it proved to be reliable and the ringer generator is sufficient to power 4-5 phones at minimum, which is enough for most applications of 551-type KSUs. I have one ringing phone per floor in my house which is more than enough when it rings. There is also a plan to connect a central ringer (Western Electric “Chime” ringer) on the same pair to announce the call on the staircase.

Overall view of the system:
[Linked Image from i.postimg.cc]
Posted By: hbiss Re: WECO 551B Ringers and Buzzers??? - 10/30/19 04:29 PM
I think I would have found a better place to put that so it doesn't cover the block.

-Hal
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 10/30/19 07:32 PM
Thanks for critics, but I do not touch that part of 66 block ever since I’ve punched down the incoming lines and ringers/buzzers. It is rather a question of cosmetic or aesthetic considerations - or personal taste. Even if I need access to the entire 66 block it is only one screw to loose and then the whole thing can be turned up or down, opening access to all rows of contacts.

But for sure you can find an alternative place as well. E.g. each 551C KSU has a provision for a fifth 400-type line card just missing the card connector and wiring (horizontal slot below the four vertical slots for KTUs and above the interruptor). I suspect there was a plan at Bell Labs to furnish 551C with 5-lines capabilities, however it was abandoned due to not enough space on the 66 block and the use of liquid Mercury contact relay in the later 400-type line cards, which should be only installed vertically.

In principle, anyone can add the 400-type line card connector there and wire it to a small extra 66-type block. Alternatively this ringer card can be cut to fit that slot.

Because I considered adding the fifth line to this KSU (before acquiring 584C panels and Call Director sets), I didn’t bother to look for another place for the ringer option. Now this is not needed on that KSU.
Posted By: hbiss Re: WECO 551B Ringers and Buzzers??? - 10/30/19 11:41 PM
How about in a box external to the KSU?

-Hal
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 10/31/19 07:53 AM
Not for me. I don’t want the wall in my office to look messy.
Posted By: Greg Ercolano Re: WECO 551B Ringers and Buzzers??? - 11/01/19 07:30 AM
Those PowerDSINE ring generators are great.. And at $15 per device, very cost effective. And yes, can confirm they can run at least 4 phones, if not more.

I think someone in Israel must've purchased the whole stock from the company when PowerDSINE got bought out, as they're selling them on Ebay and Amazon.

It puts out a 20Hz ring (instead of the 118A's 30Hz), which seems better for my quiet office. 30Hz sounds a bit too strident. But I could see 30Hz being good for a busy office environment with lots of selectric typewriters clicking away.

I mounted mine to a backboard using 4 drywall screws arranged around the edges of the module, using rubber shielding cut off from an outdoor extension cord to act as "rubber bumpers" for compression to hold the module firmly in place, as it has no mounting holes to speak of. It uses 12VDC, and has a small pigtail of 5 wires coming off it that terminates in a 6pin SIP connector, which plugs right into my KSU board, which provides the matching 6 pin header for their connector. There's another PowerDSINE model I have which operates on 24VDC; it is intended for PCB mounting, having a collection of pins on the back. And it can output either 17Hz, 20Hz, or 25Hz. I think it can ring more phones than the 12V model.
Posted By: RedBul Re: WECO 551B Ringers and Buzzers??? - 11/01/19 02:18 PM
Hi Greg,

Yes, I believe the whole production of these PowerDSINE modules was in Israel. The ones I have purchased from there have only a different label (private label or out of the books production, I believe). But the unit is the same. All units I have are dated in production between 1993 and 1996 - so I assume when the PowerDSINE was bought out, someone just forgot to take out the stock from Israel production and it was sitting there all these years. As you can imagine since that time production of analog subscribed line PBXs requiring ringing generators went down to almost zero. So a barn-load of these modules can be now a huge inventory for limited number of telephone collectors.

Yes, I confirm this works great on 1A2 and unless you plan to feed a real industrial building with that system, in any private house installation it is enough to feed the whole system. I have 3 stories in my house plus a basement. So when just 4 telephones are ringing from this unit - I can here it from anywhere in the house or from the backyard. My wife flinches when it happens. So it's enough power indeed.

P.S. I believe I have the 24VDC version as well. It has no wires and designed for trough hole mounting on the PCB. Connection legs are somehow fragile, so if it cracks out - the unit becomes useless as the whole thing is potted in ceramics. I believe there was also a bigger power item with 48VDC voltage - for bigger PBX. But unless you have the real exchange with power plant giving the 48VDC - it is difficult to power it from the 1A2 shoe box.
Posted By: jeffmoss26 Re: WECO 551B Ringers and Buzzers??? - 11/03/19 12:07 AM
Greg, can you post pictures of how yours is installed?
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