VTech Computers

Laser 50

Overview

The Laser 50 (Laser One in France) is an educational computer from VTech (Video Technology) from 1984 (some sites specify 1985) which could run in one of six different modes, including computer (BASIC) and scientific calculator mode. You may like to check out a video I did on the Laser 50 before reading on for further information:

Small and light, the Laser 50 runs off four AA (UM-3) batteries (VTech claimed the Laser 50 to run for 200 hours when running on batteries) or an external power adaptor, and will switch off automatically if a key hasn't been pressed in 2.5 minutes but your BASIC program(s) will be retained. Just switch the computer off and on again to get back to your program.

The computer features a Z80A CPU running at 3.58 MHz, along with 2KB RAM (expandable to 18KB), 12KB ROM, and beeper capable of a single voice and 3 octaves, and measures 27.5 x 16.3 x 4.2cm (WDH) and weighs just 700g.

Originally, the computer was boxed with the Tutorial book, which I found to be well written, as if designed for the average person rather than just technical individuals, and contains some amusing drawings splitting up the detailed information on using the computer.

There is a small knob either side of the Laser 50 to tilt the computer and on the left side is the power switch. Looking at the computer's underside there is a carry handle that can be rotated outward (it could perhaps also be used to prop up the computer more than the feet). A module can be inserted by removing the bottom door, sliding outwards, exposing the 2 edge connectors, and the batteries can be inserted by taking out the battery cover. At the rear is the expansion edge connector, power adapter socket, and 3.5mm audio port for connection to a tape recorder to allow saving and loading programs.

Unlike other computers of the time, the Laser 50 has no ability to be connected to a TV or monitor, instead its built-in single line, 16 character monochrome text only (uppercase only) LCD provides the visual interface, featuring automatic contrast adjustment. There is also a built-in buzzer.

A unique feature of the Laser 50 is that it can store 10 separate BASIC programs (P0 - P9) across the 2KB system RAM.

Even though the Laser 50 has a full travel keyboard the keys don't have the most pleasing response and it's not practical to type fast as the keys need to be pressed quite hard to register (not sure if that's due to old age). To fit the keyboard in such a small size there have been some compromises, such as the space key, which is quite short and located where you would expect the right shift key to be.

The six different operating modes, which are written on the computer itself are:

Mode 1 : Computer (Basic)

Mode 2 : Calculator

Mode 3 : Trace on

Mode 4 : Trace off

Mode 5 : Degree

Mode 6 : Radian

However, there are actually only two main modes, Computer and Calculator, as Trace on/off enable/disable the debugging mode when in Computer mode, and Degree/Radian affect both Computer and Calculator modes in terms of handling angles.

When powered on, the Laser 50 defaults to Computer mode (likely what most people would want to use) and you will see a flashing cursor. The LCD indicates the mode the computer is in using various indicators, example, 'COMP' is Computer mode. To change mode, press and release the 'MODE' key below the LCD then press the appropriate number  (listed above) to change to that mode. For example, to change to Calculator mode, press Mode and then 2.

In calculator mode you can give the computer simple problems, such as addition, by typing a number, then '+' (accessed with shift + P), another number, and then return to get the result. There are also a range of functions (log, sin, add, etc), accessible by pressing the key that has it written on (no need to press shift), with 'R' giving 'SIN', for example. The SIN function requires parentheses, of course, but you don't get them from shift + '8' or '9' even though those numbers have the requried symbols on them, instead you use the semi-colon/colon keys (without shift).

If you make a mistake before pressing return, use the left/right arrow keys (under the LCD) to move the cursor and type the correction(s), there is no actual delete key from what I can see. If you get an error when you press return, use the AC key to clear the line. 

To return to Computer mode press Mode and then 1; note that if you switch between modes your BASIC program(s) will remain. In Computer mode you program the Laser in BASIC, a popular entry-level programming language found on many retro computers. You can type commands without a line number, known as immediate mode, and they will be executed at once. For example:

PRINT "HELLO"

When you press return, 'HELLO' will be displayed - press return to clear the line.

Although keywords are typed in full there are some shortcuts, for example, shift + P for PRINT ('PRINT' is written on the 'P' key).

If instead we put a line number before the BASIC statement, like this:

10 PRINT "HELLO"

When you press return the program line will be stored to memory but not executed until you type:

RUN

Now when you press return you'll see 'HELLO' displayed. This is called deferred mode.

The Laser 50 can store 10 BASIC programs (P0 to P9) across its memory, with P0 being the default, and you can switch between them by pressing Prog and then the program number. The currently selected program number flashes at the top of the LCD and if you also have a program in another slot the program number will be displayed at top of screen but will not flash, helping you to keep track of your programs.

The LCD will start scrolling after you type the 16th character, a line cannot contain contain more than 40 characters; when you get near the limit the cursor will change to a flashing block. You cannot combine multiple BASIC statements on the same line even if you try to use a colon to do so, you will get an error when you press return. If you try to PRINT a string longer than the display if will only display the first part but then you can use the arrow keys left/right to scroll through the string.

The computer does have some very limited sound capabilities, which can be accessed in BASIC using the SOUND command. For example:

SOUND 3, 0

Creates a short, high pitched sound.

Although the somewhat unusual keyboard and small display takes some of the enjoyment out of using the Laser 50, it's still a neat bit of kit that serves as a good introduction to BASIC without having to hook up a power supply and TV. Being able to store 10 separate BASIC programs, even if the Laser's built-in memory is very limited, sets it apart from other computers available at the time, although more expensive computers had access to disk drives, which gave quick access to even larger programs from a single location.

The Advantech I.Q. Unlimited computer from VTech, available from 1991, can be seen as a successor to the Laser 50, featuring a single line LCD but with the ability to also connect to a TV/monitor, and having more advanced software integrated. You can watch a video from YouTuber The 8-Bit Guy covering the computer:

Tips

The BASIC program(s) will be retained for about 30 seconds with the batteries removed, giving you enough time to put in new batteries.

If you buy a Laser 50 second hand it's a good idea to check for battery leak. Do not keep batteries in for long period of disuse to avoid battery leak.

Not all BASIC commands can be used in immediate mode.

Use shift + AC to exit a running BASIC program.

Tape filenames only have five significant characters.

The Laser 50 will happily run off a 5V external power supply (tested with no expansions fitted), which is convenient considering the abundance of USB power supplies that can be repurposed.

All content of this and related pages is copyright (c) James S. 2023