WACCI 136 Index - Home Page www.wacci.org.uk

Unfinished Business: SCART Connections part two

In WACCI 135, Terry Ward explained the ins and outs of SCART connections, used to connect audio and video equipment together. We conclude his article below

Function Switching (pin 8)
Logical �0�: zero to +2.0V.
Logical �1�: +9.5V to +12V.
Input resistance: less than 10 kOhms.
Input capacitance: less than 2 nFarad.
Load resistance for compliance testing: -10 kOhms.
When contact acts as an output, output resistance less than 1 kOhm.

Blanking (pin 16)
Logical �0�: zero to +0.4V.
Logical �1�: +1.0V to +3.0V.
Impedance: 75 ohms.
Logic �1� corresponds to blanking active; the external Red, Green and Blue primary colour signals are then displayed on the screen.

Cordsets
A number of different connecting cables are available, as follows:
  Type U (Universal): where all the 21 contacts are made at each end. Coded or coloured black.
  Type V (Universal minus audio signals). Includes all the inter-connections of contacts 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and 21. Coded or coloured white.
  Type C (Universal minus RGB colour signals). Includes all the inter-connections of contacts 1, 2, 3, 4, 6, 8, 10, 12, 17, 18, 19, 20, and 21. Coded or coloured grey.
  Type A (Universal minus video signals). Includes all the inter-connections of contacts 1, 2, 3, 4, 6, 8, 10, 12, and 21. Coded or coloured yellow.
  Also available are SCART plugs with individual connectors on the other end � Phono, Co-axial, DIN with various number of pins, etc. � and a cable to a box with a number of SCART sockets, which allows a number of units to be inter-connected.
  Cordsets which have the same connectors at each end, i.e. two plugs with male pins or two sockets with female connectors, have the audio and composite video connections crossed over. So for example, pin 3 at one end is connected to pin 6 at the other, hence interconnecting the audio signals between the two pieces of equipment.
  Similarly, pin 19 and pin 20 are crossed in the cable to connect the composite input and output video signals of two units.
  Cordsets which have a plug at one end and a socket at the other do not have any connections crossed over, since they are really just extension cordsets.

WACCI 136 Index - Home Page www.wacci.org.uk