110-type block wiring scheme
110-type wiring block consists of four 25-pair connector strips. Each can be marked with five different "Tip" colors - white, red, black (usually dark blue), yellow, violet.
Connection blocks are always marked with five "Ring" colors - blue, orange, green, brown, gray. Most of the connection blocks
Connection blocks are made 3, 4 or 5-pair sizes. Four and five-pairs sized connection blocks are the most commonly used ones