PS2 connections in Olimex LPC2478 Devkit schematics

There seems to be something wrong with the PS2 connections in Olimex LPC2478 schematics.

The PS2 connector datasheet does not show pin no.4 whereas +5V have been connected to pin no.4 of PS2 connector in the LPC2478 schematics…

Can anyone help me with this ??