The Siren Board

So I was looking at the ASC sirens and noticed that there are 3 different logos you see on them. There's the circular one with the arrows, the blue square one that says "American signal corporation" and then there's the new logo that just says "ASC". does anybody know which order these were made in or the years these logos were used?

I believe the blue one came when ACA changed to ASC in the early 90s until they switched to the circular one around 2006. The current logo came about a year ago.

Thanks!