# What does the red symbol mean here?

I found this symbol on the schematics of an FPGA board. AIN stand for Analog input.

## 1 Answer

If you didn't cut off the picture, you'd see the wires are labelled AIN15_P, AIN15_N, AIN16_P, AIN16_N. The red symbol tells Altium that these signals (each matching P and N pair) should be considered a differential pair.

This can allow the layout tool to invoke special design rules for these nets, and the autorouter or interactive router to treat them specially.

• Thanks. I cut it to focus on the symbol. This is from the schematics for Digilent's Cmod A7 board. – kchak Nov 11 '16 at 8:26
• One question though, is this Altium Specific or does KiCad also have these directives? – kchak Nov 11 '16 at 8:35
• No, this is a specific "directive" of Altium. I'm not sure if Kicad has something like this. At least not with the same symbol – Jesus Castane Nov 11 '16 at 9:24