Calculators: Handheld: Adler 81CS (aka
EC41)


Size
(approx):

78mm
x 147mm x 15mm (w,h,d)
Weight 112g excluding batteries

Power:

3.0V
DC, 2 x AA size batteries. Also
accepts adapter/charger (undefined) through a socket on the top side on
the left. 
Case: 
Slim
tall (squeaky) case made from matt black plastic with a full front wrap
around aluminium panel. The
latter is printed with black text for the switch labels.
Large display escutcheon is actually the front of the case showing
through. And is printed silver with the make and model number.
Small green display filter gives a very bright image.
The upper escutcheon is so large as this is the section that sits
under the PVC pocket in the wallet. Colourful
keys are soft but work well. 
Display: 
8
digit green VFD (ninth digit for error, memory and negative flags) 
Features: 
4
function calculator with percentages, delta percentage, change sign,
powers, reciprocal, square root, pi and four function memory.
Switch for algebraic / business input principles.
Switch for summation of answers to memory.
Switch for Floating/0/2/3 decimal points.
On/off switch can also be set to “5/4” round down position. 
Age: 
197? 
Manufacturer: 
TA
Vertriebs GmbH, D8500 Nurnberg, Germany.
Type EC 41, Serial No. on battery cover 72735774 
Comments: 
Quality
calculator from Adler adopting the leading edge idea of a
“wallet cover”. However,
just to be different the holding pocket is at the top not the bottom,
which was more common. Host
of features and a switch to get rid of that annoying Business input mode. However, switchable reverse polish notation is very unusual. The
original case is black stiff plastic with a PVC pocket on the left for the
calculator and one on the right, presumably for the manual. 
Components: 

Boards: 

Construction: 
Cannot find an easy way to open
it without the possibility of damage. 
Logic comments: 
The
(C) button is used to clear last entry of a number and pressed again to
clear the whole calculator 

Overflow
on number input is suppressed; typing in a nine digit number ignores the
last digit 

An
overflow error displays the result and "C" in the far left
(ninth) digit ("E" if negative) and is recoverable using (C). 

Divide
by zero results in a "C"
which is not recoverable. 

There
is automatic constant on all four functions


Negative
numbers are flagged by a "" sign in the fare left (ninth) digit
thereby allowing full eight digit negative numbers. 

Memory
store is indicated by the far left (ninth) digit decimal point. 

A
total accumulator for the memory can be switched on with the Σ
switch. 

The
change sign function can be used in mid number entry 

Square
roots of negative numbers are not allowed; the result is displayed with
“E” in the far left (ninth) digit and is recoverable using (C) 

The
business input mode is Reverse Polish Notation (RPN); the algebraic is as
you would expect from a standard calculator.
In RPN mode to
work out 39 key in (3)(+)(9)(). Algebraic
input mode is (3)()(9)(=) as expected. 


