MPO (Multi-Fiber Push-on) is the first generation of clip clamping multi-core optical fiber connector. MTP® is a registered trademark of US Conec Ltd. , which is an advanced version of MPO, with better mechanical and optical performance. They look alike and are completely compatible and intermateable. MTP/MPO cables are composed of MTP/MPO connectors and optical fibers. MTP/MPO connectors have a female type (without pins) or a male one (with pins) as shown in Figure 1. The position of guide grooves also results in "Key Up"and "Key Down" MTP/MPO connectors. And a white dot is for identifying fiber position in connectors. MTP/MPO connectors largely increase the cable density and save circuit card and rack space, which are well suited for current 40G/100G cabling and future network speed upgrades.