Retro Review: Sharp Scientific Computer EL-5500 III
Type: Scientific, BASIC
Years Made: 1985 - 1991
Batteries: 2 CR-2032 batteries
Memory/RAM: 6,878 bytes
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 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 var = starting value TO ending value [ STEP increment ] … NEXT var
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.
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. (http://www.gbfans.com/equipment/other/radio-shack-pc-4-calculator/ )
This blog is property of Edward Shore, 2017