Use the Spectrum 128 style menu below to navigate to the various sections detailing the SCART cable.
A SCART socket can accept three types of video signal - RGB, S-video and composite video. A SCART socket will support either RGB and composite video, or S-video and composite video.
TV sets that have two SCART sockets will sometimes have one socket that supports RGB / composite video and the other that supports S-video / composite video.
The layout of the SCART socket (also known as a Peritel or a Euro connector) is as follows:
The signals available from a SCART socket supporting RGB are shown below. For reference, the pins that
are used on an S-video enabled SCART socket are shown in brackets.
| Pin |
Signal |
Level |
| 1 | Audio Output Right | 0.5V RMS, <1k output impedance |
| 2 | Audio Input Right | 0.5V RMS, >10k input impedance |
| 3 | Audio Output Left | 0.5V RMS, <1k output impedance |
| 4 | Audio Ground | 0 Volts |
| 5 | Blue Video Ground | 0 Volts |
| 6 | Audio Input Left | 0.5V RMS, >10k input impedance |
| 7 | Blue Video | 0.7V, 75 ohm input and output impedance |
| 8 | Function Switching | 0 to 2V = TV (default option if pin unconnected).
5 to 8V = TV wide screen.
9.5 to 12V = AV mode.
>10k input impedance
[When an AV source becomes active it sets 12V on pin 8 and causes the TV to automatically switch to that SCART input. When the source stops, the signal returns to 0V and TV viewing is resumed. If a 16:9 program is present, the source raises the signal on pin 8 to only 5V.] |
| 9 | Green Video Ground | 0 Volts |
| 10 | Comms Data Line 2 | This signal allows devices to communicate serial data |
| 11 | Green Video | 0.7V, 75 ohm input and output impedance |
| 12 | Comms Data Line 1 | This signal allows devices to communicate serial data |
| 13 | Red Video Ground
(Chrominance Ground) | 0 Volts |
| 14 | Comms Data Ground | 0 Volts |
| 15 | Red Video
(Chrominance Input / Output) | 0.7V, 75 ohm input and output impedance
(0.3V, 75 ohm input and output impedance) |
| 16 | Blanking | 75 ohm input and output impedance.
0V to 0.4V: TV is driven by the composite video input signal on pin 20, with transparent overlay of the Red, Green and Blue signals (default option if pin unconnected).
1V to 3V: TV is driven by the Red, Green, Blue signals and composite sync signal on pin 20. |
| 17 | Video Ground
(Luminance Ground) | 0 Volts |
| 18 | Blanking Ground | 0 Volts |
| 19 | Video Output
(Luminance Output) | 1V [sync 0V - 0.3V, data 0.3V - 1V], 75 ohm output impedance
(1V including sync, 75 ohm output impedance) |
| 20 | Video Input
(Luminance Input) | 1V [sync 0V - 0.3V, data 0.3V - 1V], 75 ohm input impedance
(1V including sync, 75 ohm output impedance) |
| 21 | Screen/Shield | 0 Volts |
|
The FUNCTION SWITCHING signal (pin 8) is used to instruct the TV set to automatically switch to show the SCART input, and
the BLANKING signal (pin 16) is used to inform the TV set
whether to show a composite video or RGB signal from that SCART socket. If the BLANKING signal is left disconnected then composite video is the
default AV input type. If the FUNCTION SWITCHING signal is left disconnected then the AV input must be selected manually.
The table below shows the different permutations:
FUNCTION SWITCHING
(Pin 8) |
BLANKING
(Pin 16) |
TV Mode |
| 0V - 2V | 0V - 0.4V | Composite Video, Manual Selection |
| 0V - 2V | 1V - 3V | RGB, Manual Selection |
| 9.5V - 12V | 0V - 0.4V | Composite Video, Automatic Selection |
| 9.5V - 12V | 1V - 3V | RGB, Automatic Selection |
