HP-12C gets 'Entry-RPN' or Error in the QSG?

[Thomas Klemm]

(07-05-2014 09:26 PM)Joe Horn Wrote:  My point remains the same: the underlined ENTER above is pressed after a number, not after an operation. Pressing ENTER after an operation is optional on all HP RPN calculators. Since this is certainly correct, and since HP's statement can be understood that way, it seems clear to me that that's what they intended it to mean. They clearly did not write it clearly.

Maybe the context is missing. Thus I'm adding the previous sentence:

Quote:Reverse Polish Notation (RPN) Mode
(...)
In RPN mode, numbers are entered first, separated by pressing [ENTER], followed by an operation key. Pressing [ENTER] is optional after entering a number, if the next key pressed is an operation.

This is from the HP-12C Owner's Handbook:

Quote:Simple Arithmetic Calculations
(...)
Pressing [ENTER] tells the calculator that you have completed entering the number: it terminates digit entry. You need not press [ENTER] after keying in the second number because the [+], [−], [×], and [÷] keys also terminate digit entry.

Thus it's already wrong in the original. It's not optional to press the [ENTER] key: it's wrong to do it in this case.

Let me write your example in two lines:
2 ENTER 3 +
ENTER 4 +

This case is handled in the next section:

Quote:Chain Calculations
Whenever an answer has just been calculated and is therefore in the display, you can perform another operation with this number by simply keying in the second number and then pressing the
operation key: you need not press [ENTER] to separate the second number from the first. This is because when a number is keyed in after a function key (such as [+], [−], [×], [÷], etc.) is pressed, the result of that prior calculation is stored inside the calculator − just as when the [ENTER] key is pressed.

While that ENTER is optional in the case of the HP-12C it is not true for the HP-48 when calculating 6×(2 + 3 + 4):
6 ENTER
2 ENTER 3 +
ENTER 4 +
×

You either get 45 or 54.

I still have difficulties to follow how you end up with:

Quote:In "Operation [ENTER] Number", the ENTER is optional.

Wouldn't that rather be:
Pressing [ENTER] is optional before entering a number, if the previous key pressed is an operation.

Cheers
Thomas