Thursday, January 12, 2017

Retro Review: Sharp Scientific Computer EL-5500 III

Retro Review:  Sharp Scientific Computer EL-5500 III

Company:  Sharp
Type:  Scientific, BASIC
Years Made: 1985 - 1991
Batteries:  2 CR-2032 batteries
Memory/RAM: 6,878 bytes

Basic Features

The EL-5500 III operates in two main modes:  CALC (calculator) and BASIC (programming mode).  The CALC mode has two additional sub-modes:  Matrices and Statistics (Linear Regression).   You can also convert numbers between Decimal (base 10) and Hexadecimal (base 16). 

The matrix mode uses RAM and has two matrices in storage: X and Y.  Thankfully, Sharp printed matrix operations on their hard case, includes arithmetic, scalar arithmetic, inverse, squaring, transpose, and determinant.  Given how the EL-5500 III has was released over 30 years ago, I image someone has come up with a good program to find eigenvalues.   X not only serves an input matrix but an output. With the one line screen, elements are shown one at a time.

In CALC mode, calculations are in AOS mode (algebraic, with the one-variable argument functions such as the logarithmic and trig functions are executed after the number is entered), and the equals key ( [ = ] ) completes operations.  However, in BASIC mode, calculations are entered the way they are written, and they are completed when the [ ENTER ] key is pressed.

For example:  to calculate log(6):
CALC Mode:  6 [ log ]
BASIC Mode:  [ log ] 6 [ ENTER ]

There is no built-in complex number mode.

The Keyboard

The keys are small, but no so small that I don’t have to use a stylus or aid to press them.  The keys are easy to the touch.  I am also impressed on how light the keyboard is, which is impressive for 1980s portable keyboard. Yet the keyboard is steady and the keys give a solid response.  Sharp did a great job with this model.


As mentioned before, the EL-5500 III has 6,878 bytes, somewhat comparable to the TI-74.  Also similar to the TI-74, there is only one program space.  You can fit multiple programs in the EL-5500 III as long as you organize your line numbers correctly.  However, the EL-5500 III has definable keys with the following available labels: A, S, D, F, G, H, J, K,L, ‘, Z, X, C, C, V, B, N, M, SPC. 

To label a program, follow this format:

Line number  “key” : command

Use the [DEF] key to run labeled programs. 

The EL-5500 III has a beep sound (via BEEP command).  I think am I going to start using beeps in programs when I can. 

The ability to type lower case is present through the [SML] which toggles lower case on and off.

The classic mathematical BASIC commands are available:  DELETE, NEW, GOTO, STR$, VAL, DATA, READ, DIM, FOR loops, IF tests, GOSUB, INPUT, PRINT, ON GOTO/GOSUB, and the almost completely unnecessary LET.

LIST is used instead of FETCH.

FOR loops:
FOR var = starting value TO ending value [ STEP increment ] … NEXT var

IF tests:
IF conditional test THEN do this one command if test is true
IF conditional test THEN go to this line number (no GOTO is necessary)

LET assigns a value to a variable.  However it is not required.  For example, both statements listed will store 5 to the variable A:
LET A = 5
A = 5

Strings are concentrated with a plus sign while multiple commands can be stringed together with a colon.

Line numbers are needed to organize the statements.  I wish line numbers were brought back in modern calculators that used basic.   According to the EL-5500 III manual, the available line numbers range from 1 to 65279.

Most commands also have short cut keywords.  For example, RAD., RADI., and RADIANS set radians mode, while P. and PR. can both be used for PRINT.  When entered, the EL-5500 III will complete the abbreviations with their full word counterparts.  This was created to save time.


The EL-5500 III can be attached to a CE-126P, a combination thermal printer and cassette player interface.  Yes, the CE-126P can be connected to a compatible cassette tape player, which the player is used to record programs.     

Final Verdict

The EL-5500 III is a pleasure to hold and use.  Despite the screen being small, the text on the screen is crisp and easy to read.  The most likely place to find EL-5500 III computers for sale is eBay, which is where I purchased mine.  Prices do vary, I paid $38.  I didn’t get any accessories though.  I recommend buying one if you are interested.  

Programs using the EL-5500 III to come in the future (along with my beloved HP 71B).

P.S. The EL-5500 III is not the calculator/computer used in the 1984 movie Ghostbusters.  That was the Radio Shack TRS-80 PC-4.  ( )


This blog is property of Edward Shore, 2017

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