A full table showing the graphics shape associated with each character,

together with the graphics control codes, is given in Appendix 2.

The printing of any of the ASCII codes 145 to 151 causes characters on the

same line to be printed in their graphics form. Upper-case letters are

unaffected:

PRINT CHR$(145);"Aa";CHR$(146);"Bb";CHR$(147);"Cc"

It is easier to appreciate the effectiveness of teletext graphics when a series of

graphics characters are displayed together:

PRINT CHR$(148);STRING$(30,"9")

Graphics characters can be displayed in double height, on defferent

backgrounds, or flashing.

You can produce the graphics control codes directly from the keyboard by

pressing and any of the function keys f1 to f7 simultaneously.

Any non-upper-case characters you subsequently type on the same line will be

displayed as graphics shapes.

Sound

Your computer contains a sound generator with four channels.

Two BASIC commands are available that give a wide degree of control over

sound. The SOUND command is used to play single notes. For example:

SOUND 1,-15,53,20

plays a note on channel 1 at maximum loudness for one second. The command

can be summarised as:

SOUND channel,loudness,pitch,duration

The first of the four parameters after SOUND denotes the channel number.

This can be 0 to 3, with channel 0 producing noises for special effects, and

channels 1 to 3 producing musical notes. For example:

SOUND 0,-15,53,20

changes only the channel number from the previous example but gives a very

different effect.

The second parameter controls the loudness or amplitude of the note, and can

have any value from -15 to 16. The loudest is -15, -14 is quieter and other

negative numbers give softer sounds up to 0, which is silence. Any positive

number from 1 to 16 indicates the sound is under the control of an ENVELOPE

command (discussed shortly).

C 64