Sinclair Simon Issue 30 Contents  ZX-81 Software Scene

Hardware World

Interface 2 alternative - high quality, lower price

THE RAM TURBO joystick interface for the Spectrum by Fleet Electronics is what Interface 2 should have been. As well as having two joystick ports, as on Interface 2, it also has a ROM cartridge slot, again like Interface 2. In addition, one of the joystick ports can be used for Kempston-compatible games and the other, if set up at switch-on, can be used as a Protek (cursor) compatible port.

The rear connector is a full Spectrum size as opposed to the Interface 2 ZX-81 size and the area surrounding the joystick port is big enough to take a standard D-type joystick connector.

To prevent users fitting the interface with the power on - the most certain way to blow up your Spectrum - it incorporates a 'Spectrum protect adaptor' a loop of plastic which covers the power socket on the Spectrum so that the lead must be removed before fitting. The only difficulty experienced with the interface was when trying to use a joystick with two independent fire buttons. When the second button was pressed the computer crashed.

If you are thinking of buying Interface 2, the RAM Turbo interface is better-designed and better value. It costs £22.95 plus £1 p&p from Ram Electronics (Fleet) Ltd, Hampshire.

Programmable interface wins praise for Protek

Protek interface

THE NEW SWITCHABLE joystick interface for the Spectrum from Protek can make games playing very much easier. All that needs to be done is to plug it into the back of the Spectrum, connect a standard joystick and load the game. A switch at the back is used to select either Protek (cursor), Kempston or Sinclair - 6, 7, 8, 9, 0 - keys and you can switch between them while the game is playing.

The interface is, as is all too common with add-ons, dead-ended, so it must be the last add-on fitted. As with the Turbo interface, it is liable to crash if used with a twin fire button joystick. Its main disadvantage is that in the Protek position the top row of keys is disabled while in the Sinclair position only the 6, 7, 8, 9 and 0 keys are disabled, which could make some games difficult to play. The switch would have to be moved, the key pressed, and the switch returned to its original position.

Despite those difficulties, which should not affect most users, the interface is easy to use and covers nearly all of the games on the market. It costs £19.95 and Protek is at West Lothian, Scotland.

Kit makes loading easy

EASYLOAD from Maplin Electronics is one of those add-ons which displays the inherent limitations of the Spectrum. It fits between the Spectrum and a tape recorder and obviates the need to swap leads when LOADing and SAVEing. It also filters the signal to improve recordings and solves the difficulties which can occur if you have an AGC on your recorder.

It is sold only in kit form and is not really for the novice but with patience construction is fairly straightforward. The instructions are thorough and include a resistor code chart for beginners. They lead you through the assembly step by step and also have a section which shows how to test it before use.

A set of additional cassette leads is supplied with the kit and, once built, it can be fitted and almost forgotten. Its only disadvantage is that it is battery-powered but a rechargeable battery can be used and a socket is incorporated to take the Spectrum power supply for charging.

At £9.95 the kit is very good value and essential if you have cassette problems. A suitable case is available for an extra £5. Contact Maplin Electronic Supplies Ltd., Essex or any of its shops.

Expansion made easy

THE NEW µSlot from Currah, noted for its µSpeech, is designed to allow two dead-ended add-ons to be fitted at the same time. The unit plugs into the back of the Spectrum and has two extender cards, one from the back and the other vertically, for the add-ons.

In that way you can use the µSpeech and joystick interface at the same time or, for full-size keyboard users, it permits a Kempston printer interface to be fitted easily.

The vertical slot may prove to be of limited use and, if you have ever experienced ZX-81 RAM pack wobble, you may find it better to use a flexible connector if you have a number of add-ons to fit. Nevertheless the µSlot has many uses.

Costing £14.95, it is available from Currah Computer Components Ltd, Cleveland.

Improved light pen

AMONG hardware releases promised by dK'tronics is a new version of its Spectrum light pen. The pen is supplied with software for both 16K and 48K versions and is a vast improvement on the old version.

dk'tronics light pen

As with the majority of light pens, there is an interface which connects to the computer, in this case the inevitable black box which fits into the user port and which is dead-ended, and a pen which plugs into the top.

The interface contains a minimum of electronics; all the work is performed by the software. A TV picture is made up by a spot of light which zig-zags down the screen. By timing how long it takes from the start of the scan to when it is picked up by the pen, the software can determine the position.

The instructions show how you can use it in your programs to choose from a menu and give you the address of the 96 bytes of code needed. In addition, the software contains a drawing program which can be used to create pictures.

The program offers a number of options to draw lines, arcs, boxes and circles, fill areas, change colours, insert text and LOAD and SAVE pictures to tape. On a 48K machine up to four screens can be kept in memory at once and then recalled, singly or one after another, to provide limited animation. The acid test of a light pen is when trying to draw freehand and that it does remarkably well. The straight lines are straight and the pen draws where it is pointing.

The only disadvantage is the lack of error-checking on some of the commands, such as when drawing an arc which goes off the screen when you are dumped back into Basic. You can return to the picture without losing it but it is annoying.

If you are looking for an accurate light pen you could do far worse than this pen which sells for £19.95, from dK'tronics Ltd, Essex and computer shops.

Programmable interface for rapid fire freaks

NEW JOYSTICK interfaces abound this month. One such is the programmable interface from Page Computing. It is of the type where you have to push a key, move the joystick, release the joystick and then release the key. That has to be done for the normal four positions, again for the four positions plus fire, again for the diagonals, again for the diagonals plus fire, and finally the fire button alone. All of that can be done with the game running, as the keyboard can still be used.

As mentioned in previous reviews of programmable interfaces the programming sequence leaves much to be desired; while it does the job it was designed to do, it is rather fiddly. Pressing up to three keys at once and moving the joystick at the same time is not the easiest feat.

The one really useful feature of the interface is a rapid fire switch. When it is put in the up position it simulates the fire-button being held down and that is very useful for the zap-everything-in-sight type of game.

At £26 plus £1 p&p the interface will be useful if you do not mind the time and hassle of programming it.

Sinclair Simon Issue 30 Contents  ZX-81 Software Scene

Sinclair User
September 1984