I recently purchased a 624 and want to be sure of the version number. There is no circle with a number on the label. The ROM (Pgm 998) display = Y501Y 990325.

At first I thought is was the "first" version (Release 1?) because it was missing the circle/number. But then I read somewhere that:

"Phones with illuminated display require KX-TA624-2 or later version" -- a 7731 phone works fine, both backlighting the screen and dialpad.

So...how does one decifer the "Y501Y 990325" to identify what Version/Release the 624 really is?

Panatic,
The "Y501Y" is actually the version.
I believe that's one of the early ones,
maybe a -1. It was manufactured March 25 of 1999.
I would open it up and see if the Eprom chips are marked.
Also, you may have a later version of a KX-TA 62477 3X8 expansion card, which will support the backlit sets.
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MrG

Thanks for the response.

The Eprom Chip indicates: Y501Y 91014 IC101

This 624 does not have an expansion card, just the original 3x8 card. This makes it still a bit confusing since I'm testing the phone [7731] on 1st port (ext 101):

"Phones with illuminated display require KX-TA624-2 or later version, for use on first eight station ports ("extensions"), but will work fine in expansion modules of earlier 624 systems."

Someone on one of the Tech Forums said the "Y5" on the ROM display indicated it was a Version/Revision 5, but that can't be true, I think!

Why is Panasonic so cryptic about easily identifying their own systems?