I've successfully connected a 4A to an older single line set without the 82 or 223 adapter blocks. They are extremely difficult to find. It does require cutting the plugs and hard wiring. I only wired it to the line, so you have to take the phone off-hook to dial, then turn on the speakerphone, and then hang up the phone. But it works great, especially for answering calls with the touch of a button.
I have a number of black 4A Precision sets for sale,, and one WE in beige, if anyone is interested.
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