Re: Setting up 555 Switchboard. Need info

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Aug 15, 2008, 5:14:59 PM8/15/08
to telecom_museum
Hi John:

Jaun wrote:
> (First post) Since I have some basic understanding of voice and data
> systems, as a "volunteer," I have been asked to set up an old 555
> Switchboard display in a new museum annex. I have no experience what-
> so-ever with the switchboard so any information will be appriciated.
> The unit is complete and was working when removed from service many
> years ago. We do have some basic line drawings but that is about it.
> Basically I would like to power it up (lights, etc) and would like to
> have it function (make patch connections, etc ) for at least two or
> three remote (initiate/answer , ring, etc) phones. Is there a "quick
> and dirty way" of doing this ??? As mentioned any suggestings would
> be appriciated. Thank you..
> John

When I set up my 555 for my museum, I used a power supply and ring
generator for powering it, and mounted them on a plywood shelf on the
bottom frame. The connectons to the phones are done using a 66 block
mounted on the wall, and connected to the board using a cable with
matching male and female amphenol connectors. I will look to see if I
can find photos taken at the time, and will send them to you. These
photos will show you the connections to the strip at the bottom for
the power and ring cennections. The lines should be clearly marked on
the block.

Quick and dirty way of doing it, no, but not terrifically difficult.


Arthur P. Bloom

Aug 15, 2008, 10:14:42 PM8/15/08
to telecom_museum

Where are you located? It might be easier to help if one of us is
close enough to travel to you.

The switchboard uses a 20B2 Power Unit, or equivalent key system power
supply. That is the Western Electric model number. The switchboard
itself is simple to power up. Although it has been quite a number of
years since I have worked on one, I believe that there are terminals
in the rear that are labelled BATT ,GRD, GEN, GEN GRD. BATT gets -24
VDC filtered battery, GEN gets 90V @30 Hz for ringing.

The trunks and stations are also labelled, or they are terminated on a
50-pair cable that is probably cut off on the board that you have. If
you call me at 631-749-0100 (anytime) we can determine what you have,
what you need, and whether I have a power supply for you.

Arthur P. Bloom, Curator,
Shelter Island Telephone Company Museum

PSTN 631-749-0100
CNet 749-0100
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