Casio FX-700P. (evaluation) David H. Ahl.

Casio FX-700P

Casio calls the FX-700P a programmable calculator, and so it is, but it also speaks a credible version of Basic. The machine is also sold by Radio Shack as the TRS-80 Pocket Computer, Model PC-4.

We tested the Casio version along with the FA-3 cassette interface, FP-12 thermal printer, and Multipac software package. All together, these components retail for about $200.

Compact and Portable

The computer is truly pocket-size, measuring just 6.5 X 2.8 X 0.4 . Its weight is 4.2 ounces. The entire system with cassette interface and printer measures a diminutive 7 X 7 X 1.5 . To this, you must add an external cassette recorder. We recommend the Panasonic RQ-8300 or Olympus C-100. Both are compact and were reliable in our tests.

All three components are battery-operated for true use-anywhere portability. Each of the units uses a different form of battery. The computer uses two lithium watch batteries with a life of about two years (or 300 hours of continuous use). The cassette interface uses two AA alkaline batteries, again with a stated life of two years. The thermal printer uses rechargeable NiCad batteries which, when fully charged, will print about 3000 lines. A basttery charger, which will fully recharge the printer batteries in about 15 hours, is included.

All three components come with vinyl pouches, but there is none for the entire assembled system.

Also available for the system is a 4K external memory module and RS-232 interface.

EX-700P Calculator/Computer

The system uses a proprietary CMOS VLSI chip. Memory capacity is not stated in the normal way (1K, 4K, etc.). Instead, the manual states that the FX-700P has "26 memories (variables) which allow 1568 program steps. The maximum number of memories can be expanded to 222. For memory expansion, program steps are converted to memory using 8 steps per memory.'

We have no idea how this translates to a comparative measure of memory. From experimentation, we deduced that a "program step' is equivalent to one character or keyword. For example, the line 30 PRINT N(I) takes eight steps--two for the number 30, one for the keyword PRINT, one each for the characters in N(I), and one for the line terminator. Thus, depending upon the type of programs you write, the FX-700P could be considered to have approximately 1.5 to 2K of storage for programs and data.

Yes, we mean programs. The FX-700P has the ability to store up to ten programs simultaneously. They are stored in areas P0 through P9 into which you log just as you would a large timesharing system. Actually, it is much easier with the FX-700P; you simply press the white S key followed by a number 0 to 9.

Interacting with the computer has many similarities to and many differences from a full-size personal computer. Naturally, the keyboard is much smaller on the FX-700P--minute you might say. The numeric keypad portion is at the right side and is laid out with normal size fingers in mind. The alphabetic keyboard follows the standard QWERTY pattern; however, the layout is rectangular and the keys are decidedly smaller than those on the numeric keypad. Thus, touch typing is totally out of the question, and even moderate speed entry is very difficult.

Each key has three meanings--the letter printed on it, a keyword or symbol printed over it in red, and a function printed under it in blue. To enter an alternative meaning, you must press the red S or blue F key prior to pressing the alpha key.

Two arrow keys move the cursor. All clear (AC) and delete (DEL) keys act as they do on a normal calculator. A STOP key halts program execution, while an execute (EXE) key acts as an all-purpose execute/return/enter key. A MODE key selects program write or run, printer on or off, program trace on or off, and angular measurement in degrees, radians, or gradients.

As with most modern calculators, if the FX-700P is not used for severla minutes, the power is automatically shut off, even though the switch may be left on.

The bad news about the FX-700P is the display. Oh, yes, it is very legible and the viewing angle of the LCD elements can be titled for best visibility, but it is only 12 characters long. When writing sprograms with two-digit line numbers, that leaves only nine characters visible for the program statement. Oh sure, there is horizontal scrolling, lines can be up to 62 characters in length, and can include multiple statements, but you see only 12 characters at a crack. "Tain't easy to debug programs this way.

Not that you will be writing very long programs with less than 1K of memory, but it seems to us that a display of 20 characters or 24 (or 31 like the TI CC-40) would have made much more sense.

Calculations and Programs

First and Foremost, the FX-700P is a calculator. Moreover, it uses true algebraic logic instead of reverse Polish notation. Parentheses have highest priority as you would expect, and, in the absence of parentheses, calculation begins from the left. Using the FX-700P as a calculator is very natural if you are "coming from' algebra. Of course, if your starting point is a calculator with a different calculation priority, the FX-700P will be a bit confusing at first.

The various functions available are the same as those in Basic, but with several notable additions. In the trig group, we find the usual SIN, COS, and TAN, but also the inverse of each one. Both natural and base 10 logs are available. Functions are incldued for square roots, exponential, integer value, absolute value, fractional value (a new one for us), sign, random number, and round off. This last one is confusing, only because it is abbreviated RND (the usual random number function call).

As with most calculators these days, memory calculations can be performed. However, because the FX-700P uses kind of a cross between Basic and calculator-speak, it seems much easier to use the memory than with a normal calculator. As with the calculations themselves, things seem rather natural.

The Basic on the FX-700P has very few bells and whistles, but is adequate. There are just 21 statements and commands, and 19 functions. All the basic Basic operators are present except those related to graphics and printing. However, there are no PEEK and POKE machine language commands, no calculated GOTOs or GOSUBs, no Boolean operators, no ON ERROR GOTOs, no CALLs, and no IF-THEN-ELSE.

Perhaps as expected, given the limited memory, there is no group of commands for manipulating data--READ, DATA, or RESTORE. On the other hand, these commands are on the TI CC-40, and we think it would not be unreasonable to expect them in a calculator/computer of this sort.

So that is what it doesn't have. Nevertheless, with what it does have, many interesting programs can be written and many complex problems can be solved. What kind of programs and problems? Read on.

Extensive Program Library

Along with the basic FX-700P, and weighing three times as much as the computer, is a paperbound book of programs. This 152-page book is titled simply, Program Library.

The book contains 73 programs in nine areas:

Mathematics 31

Mechanics 10

Statistics 13

Banking 7

Games 6

Electrical Engineering 10

Physics/Chemistry 5

Medicine 5

Navigation 2

Some of the programs in the book border on the trivial (calculation of remainder--three lines), but most are useful and decidedly non-trivial (t-distribution, Bessel functions, acidity of blood, compound annual interest, and astronomical observations).

These programs coupled with the many examples in the 70-page Instruction Manual should help most users get the most from their machines.

Cassette Interface

How much can you say about a casette interface? The interface itself is very compact (it adds about an inch to the depth of the FX-700P), and it works reliably. It ought to; it uses the old Kansas City cassette standard (remember the Altair!) of 300 bits per second. Sure, it is slow, but for the length programs you will be saving, it doesn$ht make much difference.

The cable attached ot the interface has the usual three plugs for the earphone, microphone, and motor control jacks on a standard recorder.

Programs are saved with the SAVE command and loaded with LOAD, either with or without a name specified. Data are saved with PUT and recovered with GET; again, file names are optional. One additional command may be used in conjunction with the recorder, VER, to verify if a program has been saved correctly.

FP-12 Printer

The FP-12 printer is a thermal printer that plugs into the back of the computer or the cassette interface. As mentioned earlier it is powered by rechargeable NiCad batteries, and comes with a small battery charger.

The thermal paper is 1.5 wide and the print width is 1.1 (20 characters). Paper loading is the easiest we have ever seen; the roll is simply laid in the paper compartment, and the feed switch pressed--that's it!

The MODE key on the computer turns the printer on and off. When it is on, everything that shows on the calculator display is echoed to the printer. Thus there is no need to use special printer commands such as LPRINT or LLIST; indeed, the computer doesn't recognize them. The printer prints either everything or nothing.

Actually, it is even more friendly than that. If you specify a program listing while in the run mode, program lines that require more than one printer line will be indented on the second and following lines (See Figure 1).

The printing is in black on white paper in a 5 X 7 dot matrix. Print speed is a leisurely one line per second.

Multipac Software Package

The Multipac software package was written by Sunrise Software and consists of a group of four rather incongruous programs. One is a spreadsheet, but don't get all excited. VisiCalc it is not. The spreadsheet has a maximum of five rows and five columns and simply adds the rows and columns. You use the arrow keys to more about the matrix and change values, and that is about it.

Jackpot is a simulated slot machine game that accepts your bet for each pull of the handle. After pressing EXE, you either see NO WIN or XX.00. It gets old very fast.

Fone File is a filing system for storing phone numbers. It allows the entry of up to 50 names and numbers. Just think, you can use up the entire memory of your expensive computer storing the same stuff you can write in a 59-cent address book.

Loans is a program to calculate the monthly payments for declining balance loans (are there any other kind?). A similar program is included free in the Program Library book.

As you can probably tell, we are not at all enthusiastic about. Multipac. If your dealer throws it in free with your FX-700P, fine; otherwise, save yourself the $15.

A Pocket Computer For You?

The FX-700P is compact and light-weight, as are the cassette interface and printer. Coming from Casio, they are likely to be quite reliable. All things considered, the FX-700P offers an excellent value for the price.

The bottom line question is: do you need (or want) a pocket computer? If so, the Casio FX-700P certainly merits your consideration. If you are an engineer, technician, or student, or if your work requires lots of repetitive calculations in "field' locations, then this computer would be ideal.

On the other hand, the FX-700P should not be considered a replacement for a desktop or notebook personal computer--one of those two should definitely come first. Also, don't look to it for word processing or for long, complex programs--the display will drive you crazy.

Table: Figure 1. Program listing and run of guessing game on Casio FX-700P computer and FP-12 printer.

Photo: Casio FX-700P computer is compact and lightweight.

Photo: FX-700P connected to cassette interface and printer measures only 7 X 7 .

Products: Casio FX-7005P (computer)
Radio Shack TRS-80 PC-4 (computer)