MTP® loopback modules are used widely within testing environment especially within parallel optics 40/100G networks. Devices allow verification and testing of transceivers featuring MTP® interface – 40GBASE-SR4 QSFP+ or 100GBASE-SR4 devices. Loopbacks are built to link Transmitter (TX) and Receivers (RX) positions of MTP® transceivers interfaces. MTP® loopbacks can facilitate and speed up IL testing of optical networks segments by connecting them to MTP® trunks/patch leads.