Financial calculators puzzle

[Chasfield]

I found a couple of Busicom financial calculators for sale at 5 GBP each - cheap enough! The model FN400 is clearly a Texas BA clone of some sort. But I am not sure about the DNA of the model FN200, with its extensive unit conversion functions. Picture attached.

Can anybody enlighten me?

Maybe it is a from-scratch build and they wrote their own ROM.

[Chasfield]

I dug around some more on the FN200 and discovered the exact same hardware is also sold under the Karce brand.

Other than that, this may be a case of spontaneous financial calculator generation. It just popped into existence of its own accord.

Google Karce FN200 to see the whole family at karce.com.

[Adam Vaughn]

The button layout reminds me of Casio's calculators, but their modern financial models have multi-line dot-matrix LCDs with cursor buttons, so I'm not sure. Maybe a repurposed older model?

[Chasfield]

There is an older single line Casio FC-100, which also has the 20+30 button layout. However, the function allocation is completely different (not just swapped around a bit) and there are no unit conversion functions. Older models from other manufacturers (Citizen and Sharp) have no resemblance at all. It is hard to believe that a fully function financial calculator for 5 GBP isn't a clone of something first made by somebody else.

I have ordered one up to compare with my HP12C.

[Vtile]

Canon and Aurora ?

[Chasfield]

There was the Aurora FN1000, which was an HP12C clone in portrait format, with the buttons moved around. I also found pictures of a couple of old one line display Canon financial models but those are very different.

I have received my Busicom FN200, and I would say that it is pretty decent for 5 GBP.

It computes time value of money problems at about the same speed as my HP12C and lacks only NPV and IRR cashflow functions. Its additional unit conversion functions would actually be more useful to many people and they are quite nicely implemented. One unit pair legend appears as a shifted function above each key and it is called by either of two blue arrow keys, depending on which direction you want the conversion to go.

[dm319]

The Busicom FN400 seems to have 13 digit accuracy, and it actually does pretty well, returning results on average better than most financial calculators - even the top HP ones.

The Busicom FN200 does pretty badly. It has 12 digits accuracy, but its results are at the bottom end of the results table, only just beating the original HP-27 overall.

Results are here, which is a central place to put them for the moment, but I'm running out of space editing that first post in the thread. I haven't quite updated it yet, but I'll put in a 'digit efficiency' graph at the end.