Author Topic: 500 base as a subset?  (Read 744 times)

Offline Steve

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500 base as a subset?
« on: November 19, 2014, 12:08:33 AM »

 So I picked up a 233 payphone and I'd like to use an old 500 desk set as a subset.

 do they make a subset style cover for the 500 like they do for the 302? or should I look for an old 302 base and use that instead?

any help or insights are appreciated.
If you're a long way from home,
Can't sleep at night.
Grab your telephone,
Something just ain't right.

Offline Phonesrfun

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Re: 500 base as a subset?
« Reply #1 on: November 19, 2014, 12:46:19 AM »
The 233 payphone with a G handset is meant to be used with the 425 network, which is what the 500 phone has in it.  Specifically, the phone was intended to be wired to a 685A subset.  Wiring the phone to the 500 would be similar to wiring it to a 685 but notably different because of the lack of a separate terminal strip.  Nobody that I know of makes a subset cover for a 500 base.  You would need to unhook the 500 hook switch.  If an older model 500, the "C" terminal on the 425 network is hard-wired soldered to the hook switch, rather than having a screw terminal, and you need access to the C terminal so you would need to probably clip the hook switch wire to be able to connect to it.   

Wiring the 233 to a 302 base would mean wiring the phone the same as an older model payphone, which is also very do-able, but fairly different from the published diagrams. 

The best option would be to find a 685A subset and proceed with the standard wiring.

« Last Edit: November 19, 2014, 12:50:50 AM by Phonesrfun »
-Bill G

Offline Steve

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Re: 500 base as a subset?
« Reply #2 on: November 19, 2014, 01:13:12 AM »

 Thanks for the reply Bill.

 I may go the easy route and just use an old mini pcb style network. I'm not sure where to find a 685 network that would be in my price range.

would an earlier style subset work? 
If you're a long way from home,
Can't sleep at night.
Grab your telephone,
Something just ain't right.

Offline poplar1

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Re: 500 base as a subset?
« Reply #3 on: November 19, 2014, 09:43:46 AM »
The lack of a terminal strip in a 500 or 554 base is not a problem. In a 685A, the Slate-Red ringer lead goes to 1 on the terminal strip, and there is a brown-yellow strap wire from 1 to A on the network. So placing the S-R ringer wire directly on A -- as is done in 500s -- is equivalent.

The brown strap wire (from C on the network) going to 2 on the 685A terminal strip is moved to L2 on the terminal strip when using a 685A with pay phones. With a terminal strip, the L1, L2 and G terminals on the network are not used. So these  network terminals can be used instead of the L1 and L2 terminals on the terminal strip.

The factory installed blue strap wire from RR on the network to L1 on the terminal strip is removed when using a 685A with a pay phone.

So the 1, 2, L2 and L1 terminals on the strip are no longer needed. The G and K terminals on the strip weren't being used anyway.

Reference: South Central Bell Installer-Repairman Handbook, October 1969
BSP Section 506-215-403, Issue 4, June 1968,
685A Subscriber Sets -- Used With Coin Collectors
Connections
« Last Edit: November 19, 2014, 09:56:11 AM by poplar1 »
"C'est pas une restauration, c'est une rénovation."--François Martin.