There are 4 pairs of 2 wires, for 8 overall. They are all used, but the pairs are redundant. From what I understand, when you send a positive pulse on, say, the solid blue wire, you also send a negative pulse on the stripy blue and white wire. The twisted pairs should counteract any interference, but if it doesn’t, the arrival of the bumps with opposite polarity should foolproof things a little.
There are 4 pairs of 2 wires, for 8 overall. They are all used, but the pairs are redundant. From what I understand, when you send a positive pulse on, say, the solid blue wire, you also send a negative pulse on the stripy blue and white wire. The twisted pairs should counteract any interference, but if it doesn’t, the arrival of the bumps with opposite polarity should foolproof things a little.
Oh yeah it’s called differential signalling.