Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 9, NO. 6 / JUNE 1983 / PAGE 154

The Power Case System. (evaluation) Yedidyah Langsam.

The Power Case System

One of the major disadvantages of the Apple II computer is its inability to display the lowercase alphabetic characters. Recently I had the opportunity to evaluate the Power Case System manufactured by Beaman Porter, Inc. It was a pleasant surprise to discover a product which fulfilled all my expectations and yet was eminently affordable. In use, the Power Case System is completely transparent to the programmer and enabled my department to adopt the Apple, as intelligent terminals for use with text editors available on our mainframe.

About Lowercase

Before discussing the Power Case System let us review the method by which characters are represented in the Apple and ultimately displayed on the monitor. All of the characters found on the Apple keyboard are represented internally in ASCII codes 0-127. Examination of Table 1 on page 15 of the Apple II Reference Manual reveals that these codes correspond to the upper- and lowercase alphabet, the digits from 0-9, and various punctuation marks as well as various control characters and special symbols.

When these codes are sent to the monitor for display, they are first examined by a special ROM at location A4-A5 on the main board. This ROM decodes the incoming signals and sends on the proper character to be displayed to the monitor. Unfortunately, this ROM recognizes only a limited number of ASCII codes and converts those codes which it cannot display into other displayable characters. This can easily be seen by running the program in Listing 1.

It is immediately apparent that the ROM decoder does not recognize the lowercase alphabetic ASCII codes and substitutes the uppercase letters in their place.

One other major deficiency of the Apple lies with its keyboard. The SHIFT key as it is found on the Apple has no effect on the case of the letter transmitted to the CPU.

To correct the inability of the ROM chip to display all the characters represented by the ASCII code one would only have to substitute a different ROM chip in its place. The second problem, that is the inability of the keyboard to transmit the lowercase codes, is slightly more difficult.

For example, suppose you depress only the A key without shifting. We would expect that the ASCII code 97 representing a lowercase a would be sent to the chip. Unfortunately, the Apple keyboard sends an ASCII 65 representing an uppercase A. One way to solve this problim is to write a software routine that examines incoming codes from the keyboard and transforms them to their lowercase counterparts unless a SHIFT key is depressed.

Unfortunately, and this is the catch, the SHIFT key on the Apple does not possess a code of its own, so our routine has no way of detecting whether or not the SHIFT key has been depressed.

This problem can be solved by attaching a wire from the shift key to the game socket and having our software examine the game socket for a signal. If a signal is detected at the game socket our routine lets the uppercase ASCII code through without converting it to lowercase.

This is exactly what is done by the Power Case System. Power Case is an upper/lowercase system for the Apple II revision level 7 or greater (1980 and later). It is easily installed and produces one of the clearest and crispest character sets available. The Power Case System comes with a replacement ROM chip to generate the new character set and a micro-hook jumper to connect the SHIFT key to the game socket without any soldering or other permanent changes to the Apple. In addition to the clear and easy to follow manual, the Power Case System includes, on a double sided 16-sector disk, the software routines to effect the upper/lowercase SHIFT key modification written for both Applesoft under DOS 3.3 and UCSD Pascal.

The instructions were so easy to follow, I made the modification in under 15 minutes. The installation procedure is outlined in 12 easy steps accompanied by photographs. The entire procedure is reversible so that the Apple can be returned to its original condition without voiding the warranty.

Using the System

Using the Power Case System is equally simple. An ESC ESC sequence provides the alpha shift lock. A flashing cursor indicates uppercase. The Power Case System also provides the user with many non-alphabetical characters which were previously unavailable. For example, typing ESC produces a backslash; other ESC sequences provide for {, }, [, ], and many others.

The only thing that takes some getting used to is that the cursor moves previously obtained by an ESC I, J, K or M sequence are replaced by the sequence ESC CTRL-W CTRL-A. CTRL-S or CTRL-Z respectively. Another aspect that might at first be confusing is that Applesoft, Integer, and DOS don't understand lowercase. If you type list the computer will respond with syntax error. All you have to do is place the keyboard into caps-lock and the computer will respond to LIST as before.

In addition to the basic UCLC.D routine provided on the disk you will also find programs called KEYPRINT and UCLC.P. The former is simply a program to display the ASCII code name (cr, lf, null, etc.) or decimal value of any key pressed.

UCLC.P is a routine very similar to UCLC.D except that the key sequence used to provide the various additional functions provided by the Power Case System are the same as those used to provide the corresponding functions while using Pascal. Thus a programmer who works with both Pascal and Basic will not be confused by two different key sequences.

To use the Power Case System from Pascal, a routine for updating the SYSTEM.APPLE file on the APPLE1 disk, is provided on the reverse side of the Power Case disk. Clear and easy to follow instructions for updating SYSTEM.APPLE using either a one- or two-drive system are given in the instruction manual. Once the update has been performed, an entire array of functions is added to those previously available with the Pascal System.

Since I am not familiar with the Apple Pascal System, suffice it to say that the documentation provided seems clear and complete. The Power Case System was initially designed to be used with the Power Text Word Processing System (also a product of Beaman Porter) which is a Pascal System. You are, therefore, assured that Pascal and the Power Case System are totally compatible.

Although no mention of CP/M and the Z80 softcard can be found in the Power Case documentation, I have found that the Power Case System works very well under CP/M. CP/M, as provided with the Z80 softcard, is configured to change all lowercase characters into uppercase letters. Using the CONFIGIO routine as described on page 5-16 of the Microsoft Softcard documentation, the CP/M system disk may be reconfigured to take advantage of the Power Case ROM chip to display lowercase text. For upper/lowercase text, the Microsoft Softcard documentation contains a simple machine language routine which can be patched into the CP/M BIOS system.

As far as compatibility of Power Case with smart terminal packages, I have used it successfully with both Data Capture 4.0 and Z-Term to communicate with compuserve and other time-sharing systems.

In conclusion, the Power Case System is easy to use and works well with all three commonly used Apple operating systems. It is nice to see a product which delivers what it promises at a very affordable price. I can recommend this product without any reservation.

Beaman Porter, Inc., Pleasant Ridge Rd., Harrison, NY 10528.

Table: Listing 1.

Products: Beaman Porter Power Case System (editing equipment)