A patchboard having at least four socket blocks and at least one fastening element, wherein the individual box-shaped socket blocks are arranged in relation to each other in such a way that each socket block is connected to at least one further socket block in both x and y directions, end and side faces of the socket blocks each have at least one connection region for connecting to another socket block. A fastening element is arranged in the center between four socket blocks and is a pin having a gear-shaped cross-section having four ridge-shaped teeth, a groove being formed on each of the four longitudinal edges of the individual socket blocks, which grooves have a first section and at least one second section adjoining the first section. The pin can be rotated about its longitudinal axis when the pin is arranged in the second section of the grooves.