According a prospect, DIEHL (Germany) was the first company to introduce
a desktop-calculator with a real decimal-automatic.
The machine was called DIEHL Transmatic (1963).
The model-history of DIEHL-calcs is rather confusing,
With this page, I'm trying to collect and show some info I've got on elec. DIEHL-machines.

 

Combitron ^
Programmable 16-digit printer model, 25kg.
(see also: 'Program Example', further on)
Full discrete-components logic, auto-decimal (max. 8 positions),
66 internal program-steps, storable on an external punch strip reader (Dilector)
When input is made, small lights are lighting up, showing how much numbers are inserted.
After turning on, the machine is 'booting' and does read a program
that's stored on a internal punched strip.

Combitron S ^
(~1969) Programmable, 11 memories,
 120 internal program-steps, storable on an external punch strip reader (Dilector)

Decitron S ^
(~1969) Pre-Programmed functions, 10 memories

 

Producta ^
 Auto-decimal, Constant
New keyboard-input is possible during calculation-flow

Decima S ^

Dilector (on the left) ^
 Punch strip reader for the 'Combitron'- and 'Algotronic'-models.
An Eight-channel strip stores programs and additional constants.
A specially developed strip-tape can hold 700 instructions.
The device can also be used for storing and reading other digital data.

Strip Puncher ELS830 ^
 The ELS810 and ELS830 Strip Punchers are completing the DIEHL product range.
The ELS830 can handle a one-Inch-width strip and
supports all strips from five to eight channel.

 

Other DIEHL-models/systems (have no info on these):
Alphatronic, Meritronic

Systems:

Deltronic ^
10 memories, Square root
Rounding-off setup.

Decitronic ^
 Pre-Programmed functions,
Multiple Percentage-functions,
Has also the same features as the 'Deltronic'-model.

Sigmatronic ^
 Pre-Programmed statistical functions,
e.g. linear regression, arithmetic mid, correlation-value.
Has also the same features as the 'Deltronic'-model.

Combitronic ^
10 Constant-memories and 10 Program-memories
e.g. Commands for Jump [J], Conditional Jump [CJ]
 Has also the same features as the 'Deltronic'-model.

Algotronic ^
Transcendent-functions,
64 Constant-memories, 32 can be used as Program-memory (total of 320 instructions)

Program Example: