Mode conditioning patch cables are designed to connect multimode cables with single mode based transmission equipment. These cables are built in the form of a simple multimode duplex cable with a single mode to multimode offset fiber connection in one of the two legs of the cable.
When a single mode laser signal is launched in the center of a multimode cable, a phenomenon called differential mode delay occurs. Differential mode delay results in reduced bandwidth over distance. The offset of the single mode fiber core in mode conditioning patch cables reduces the effects of differential mode delay. And it also allows the single mode signal to successfully travel over the multimode fiber.
The connector abbreviation in the part number that follows the first "-", is the end that connects to the singlemode equipment (ST, SC, LC, etc.). This end has the yellow (singlemode) leg which connects to the singlemode transmit port. The other end of the patch cable connects to the multimode cable. Typically two mode conditioning cables are needed, one for each end of the multimode cable.