Sinclair ZX Spectrum Reference manual

by Steven Vickers
and Robin Bradbeer
PDF Edition 2004
prepared by Colin Woodcock,
ZXF Magazine (www.zxf.cjb.net)
© 1982 Amstrad
Amstrad has kindly given its permission for
the redistribution of its copyrighted material,
but retains that copyright.

Front cover illustration by John Harris of Young Artists

Contents
CHAPTER 1 The computer and setting it up. Page 5
CHAPTER 2 The keyboard. Page 8
CHAPTER 3 Numbers, letters and the computer as a calculator. Page 11
CHAPTER 4 Some simple commands. Page 14
CHAPTER 5 Simple programming. Page 17
CHAPTER 6 Using the cassette recorder. Page 21
CHAPTER 7 Colours. Page 25
CHAPTER 8 Sound. Page 27
CHAPTER 9 Inside the case. Page 29

1. The Computer and setting it up
This short booklet has been written for two types of people. First, those who know
nothing, or next to nothing, about computers, and, secondly, for those who are
familiar with computer based systems but who like to read instruction booklets
before plugging anything in.
There is a second, thicker book which is the BASIC programming manual. This
should not be read by the novice computer user until this booklet has been read
and understood.
Unpacking the ZX Spectrum, you will have found:
1This introductory booklet and the BASIC programming manual,
2The computer. This has three jack sockets (marked 9V DC IN, EAR and MIC),
one TV socket, and an edge connector on the back where you can plug in extra
equipment. It has no switches - to turn it on you just connect it to the power supply.
3 A power supply. This converts mains electricity into the form that the ZX
Spectrum uses. If you want to use your own power supply, it should give 9 volts DC
at 1.4 A unregulated.
4An aerial lead about 2 metres long, which connects the computer to a television.
5 A pair of leads about 75 cms long with 3.5 mm jack plugs at each end. These
connect the computer to a cassette recorder.
You will also need a television - the ZX Spectrum can work without one, but you
won't be able to see what it is doing! It must be a UHF television (in the UK); if it is
not built to receive BBC2 then it is no good. As its name implies, the ZX Spectrum
gives a colour signal which if you have a colour television, will produce a colour
picture. If you only have a black and white television, then the colour will appear as
black, white and six different shades of grey; but apart from that, a black and white
television will work just as well as a colour television.
The components of the system should now be interconnected thus:
5

Mains
electricity
Power
supply
unit
Mains lead
TV
mains
lead
TV
UHF
Aerial
Socket
TV EAR MIC 9V DC in
Figure 1
If your television has two aerial sockets marked UHF and VHF, then use the UHF
one (UK).
Turn the power on and switch on the television. You now need to tune the
television in The ZX Spectrum operates on channel 35 UHF (UK) and when it is first
plugged in and properly tuned it gives a picture like this:
Chapter 1
When using the computer, you will probably want to turn the volume on the
television right down.
If your television has a continuously variable tuning control, then you just have to
Figure 2
6

adjust it until you get the picture shown in figure 2. Many televisions now have an
individual push button for each Station. Choose an unused one and tune it in.
For use in countries that have a different TV system to that in the UK a version
of the ZX Spectrum specially designed for that system is necessary. The UK uses
aUHF system with 625 lines and 50 frames per second. It also uses a colour
encoding system called PAL. Most countries in Western Europe (except France)
use a similar system, and the computer should operate in these countries without
any modification. The USA, Canada, and Japan, for example, use a totally different
TV system and a different version of the computer is required.
When you turn the ZX Spectrum off, all the information stored in it is lost, One
way of keeping it for later is by recording it on a cassette tape. You can also buy
tapes that other people have prepared and so run their programs. The lead with
two jack plugs at each end is used to connect a standard cassette recorder to the
ZX Spectrum. Chapter 8 of this booklet explains this further.
Now that you have set up the computer, you will want to use it. The rest of this
booklet tells you how to do that; but in your impatience you will probably already
have started pressing the keys on the keyboard, and discovered that this removes
the copyright message. This is good; you cannot harm the computer in this way.
Be bold. Experiment. If you get stuck, remember that you can always reset the
computer to the original picture with the copyright message by taking out the '9V
DC IN' plug and putting it back again. This should be the last resort because you
lose all the information in the computer.
WARNING. Do not try to use the ZX 16K RAM with the ZX Spectrum. It will not
work.
Chapter 1
7

The cursor now changes to an L,as a Letter is now expected by the computer.
Type in the letters "Hello". If there is already some other text, for example, on the
screen turn the computer of (remove the 9V plug) and start again. Use the CAPS
SHIFT key to get the upper case H.In general, anything coloured white above the
key requires CAPS SHIFT to access, and anything coloured red on the key
requires SYMBOLS SHIFT
Acommand beginning with PRINT tells the computer to write the letters enclosed
2. The Keyboard
The keyboard of the Spectrum is very similar to a standard typewriter. The letter
and number keys are in the same place; however each key can perform more than
one function. On a normal typewriter the letters appear in lower case, and when
used in conjunction with the shift key, appear as upper case (capitals). The
Spectrum keyboard is just the same.
To help you know what mode the keyboard is in, a reversed out (white on black)
letter appears on the screen indicating the position of the next character that
appears when a key is pressed. The letter is flashing to distinguish it from any
character already on the screen. It is called the cursor.
When first switched on the Spectrum shows a copyright message on the screen.
Pressing any key brings up the word printed below the letter on the key, (this is
called the keyword). This is because the computer is expecting a command from
you to tell it what to do and all commands must begin with a keyword. Unlike most
other computers the Spectrum allows you to enter keywords with only one key
depression.
For example, if the Pkey is pressed immediately after turning on, the keyword
PRINT appears on the screen. The “ symbol is marked on the Pkey as well. To
get it, you must press two keys at once; hold down the SYMBOL SHIFT key, which
is near the bottom right-hand corner of the keyboard, and while still doing that,
press the Pkey.
8
Figure 3