Bar Codes For Sorting Circa 1970

I have a 6c Suffrage FDC from 1970, one that went through the mail system, that has a bar code on its back. The spacing, size, and height differences of the bars are much the same as those that appear on the bottom front of letters today. Differences are the one from 1970 was stamped rather than sprayed on, uses purple rather than black ink, is oriented vertically, and has fewer bars. It appears on the reverse side of the cover, behind the stamp. If I were able to upload an image I would. Is this an early USPS bar code?

Perf10, there are quite a bunch of different bar codes used by the USPS. If you Google "USPS bar codes" and then click "images" you will get a whole bunch of them. Maybe you can find the one you are referring to on that page.

Peter

If you post a good quality image of the bar code I should be able to decode it for you.
Don

All the bar code images I've seen online are modern, dating since the 1990s. Except for this particular cover, I've not seen a USPS bar code on any 1970s cover.