2564 polarity guard

[podor]

Greetings! I used to be a frequent poster here a few years ago. I'm interested in getting a some of my key phones working again. I used to have a 551b and sold it to fund a new hobby. I bought the 1A2T simulator that was mentioned here. It's pretty neat, and I'll do an in depth review shortly (I smoked it hooking it up to my Panasonic 616. Long story). It passes the T/R directly to the phone, unlike a normal KSU. My 616 has the polarity reversed, which normally isn't a big deal. Can I add a polarity guard to the 2564? I see instructions for mounting but no wiring in the BSPs.

[poplar1]

From TCI Library:

[dsk]

A simple rectifier bridge does the job.   Connect it as described higher up, or read this: https://www.telephonecollectors.info/index.php/browse/bsps-bell-system/bsp-categories-by-later-division-number-by-doc/500-529-station-equipment/501-division-station-set-components/13311-501-321-100-i2-jan69-polarity-guards/file

[paul-f]

The following TCI Library search link returns the above reference (issue 2), plus several other issues of the same BSP for your reading pleasure.

https://www.telephonecollectors.info/index.php/search?q=501-321-100

(Search links are more likely to survive future software upgrades.)

[MMikeJBenN27]

I remember, as a High Schooler in the early 70s, we found what looked like a good 10 button 1500 at the dump, so we took it home and found out that you couldn't call out with it.  I wonder if it was just suffering from reversed polarity?  Touch Tone was a rarity in our neck of the woods, as Ma Bell charged an extra $10.00 per month for it.

Mike