First non-HP pocket calculator with scientific functions ?

[Accutron]

The 'Rockwell' 202SR actually began as the Unicom 202SR, and was advertised at least as early as November 1973. Rockwell had recently bought out Unicom, which was the calculator production arm of AMI (the same AMI that second-source manufactured HP calculator chips.) It's reasonably safe to assume that all of the heavy lifting to get trig into a Rockwell QIP was actually done by AMI engineers who had cut their teeth on HP chips. Later Rockwell scientific chips have poor trig performance when compared to the chips used in the 202SR and Sharp PC-1001/1002/1801 models.

The date on the PC-1801 datasheet appears to be December 1973, and may even predate the actual introduction of the calculator by some number of weeks. The earliest mention of the PC-1801 in a US publication is 1974. Given the fact that the PC-1801 is based on a Rockwell chip, proper credit for the first non-HP scientific pocket calculator definitely belongs to Rockwell/Unicom/AMI, regardless of whether the 202SR or PC-1801 came first.