What was the first calculator with R-P and P-R keys?

[EEVblog]

Long time no visit.
I'm doing video on complex numbers and wondered what was the first calulator (any brand) that had R-P and P-R keys for complex number format conversion?
I included an image of an original Casio FX-82, but there has to be eariler ones.

Thanks.
Dave.

[Didier Lachieze]

I would say the HP-45 in 1973 with ->P and ->R as primary and secondary functions.

[EEVblog]

(04-22-2022 08:36 AM)Didier Lachieze Wrote:  I would say the HP-45 in 1973 with ->P and ->R as primary and secondary functions.

Yep! Forgot about that.
1973 might be hard to beat?

[EdS2]

HP's 9100A from 1968 was by no means a handheld, but it was often described as a calculator - it has TO POLAR and TO RECT buttons.

(I checked Commodore, they came in somewhat later as far as I can tell, maybe 1976 or '77 with the 55-key M55. Edit: oh wait, 1975, the 5R39)

[pavel nemec cz]

(04-22-2022 08:49 AM)EEVblog Wrote:  

(04-22-2022 08:36 AM)Didier Lachieze Wrote:  I would say the HP-45 in 1973 with ->P and ->R as primary and secondary functions.

Yep! Forgot about that.
1973 might be hard to beat?

Mine Compucorp 326 is from 1976 but how about Compucorp 320? The instruction brochure shows the date 1972 (invaluable KW archive):
https://www.wass.net/manuals/Compucorp%20320.pdf

Some memory refresh, Dave:
EEVblog #663 0:15
https://youtu.be/ezr3CzGUVeQ

KR
P