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HP42S Up and Down arrow symbols on 82240B - Printable Version

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HP42S Up and Down arrow symbols on 82240B - tcab - 03-01-2018 10:52 PM

The HP42S uses arrow symbols for moving around a matrix

←
↑
↓
→

I'm wondering how the ↑ and ↓ characters manage to get printed on the HP 82240 printer, since those characters seem to be missing from the Roman 8 character set, or more specifically the Modified HP Roman-8 (1986), variant II (HP 82240A/B & HP-28C/S). Those characters should be printed when embedded in program listings, or I think, when the HP42S/Free42 is in trace mode...

[Image: HP82240B_printout.jpg]
Notice the left and right arrows in the middle of line five. But I cannot see the up and down arrows, so how are they printed?

I don't have a HP42S (though I do have a DM42 which runs Free42), and my 82240B has broken, so I can't investigate this further myself.

RE: HP42S Up and Down arrow symbols on 82240B - Didier Lachieze - 03-01-2018 11:16 PM

↑ is printed as ^ for example X↑2 is printed X^2
↓ is printed as v for example R↓ is printed Rv

Here is the printout of :
Code:
01 X↑2
02 R↓
03 ↑
04 ↓

on the 82240B, from the HP-42S

[Image: printout.jpg?raw=1]

RE: HP42S Up and Down arrow symbols on 82240B - PANAMATIK - 03-02-2018 08:32 AM

(03-01-2018 10:52 PM)tcab Wrote:  I'm wondering how the ↑ and ↓ characters manage to get printed on the HP 82240 printer...

The HP82240B printer has two character sets, Roman8 and ECMA. The up/down arrows are in the ECMA set. An ESC sequence can switch between the two character sets. But the above printout shows the HP-42S doesn't make use of it, I think it was designed for the HP82240A printer, which had only one character set.

Bernhard

RE: HP42S Up and Down arrow symbols on 82240B - tcab - 03-02-2018 12:23 PM

Interesting. Yes I can see all four arrow direction symbols in the ECMA-94/RPL character set, in positions 141,142,143 & 144.