The jumper plug of the blue UPC is inserted into the adapter port of the green APC. It can be inserted and the light can be received vaguely, but the link index will be significantly degraded. The mixed use of end grinding types is a typical source of invisible faults in passive links.

Three colors correspond to three end faces

• APC: green, the end face is inclined at an angle of 8 degrees, the reflected light is inclined out of the fiber core, and the return loss is not less than 60dB;
• UPC: Single mode is mostly blue, the plane is physically polished, and the return loss is not less than 50dB;
• Multi-mode: Beige appearance, no bevel grinding concept, you should be wary if you see so-called APC multi-mode products.

What will happen if you plug it in wrongly: Insertion loss jumps, return loss collapses

When the UPC plane is in contact with the APC bevel, only a linear fit remains. The typical insertion loss will jump from 0.2dB to more than 1dB, and the return loss will be greatly deteriorated. If inserted in a misaligned position for a long time, the sleeve may be pushed out by the bevel and permanently worn. For digital links that are sensitive to reflection, the direct consequences of mixed insertion are often receiving bit errors and occasional link disconnections, which appear as an abnormal reflection peak on the OTDR curve. When troubleshooting, first check the color of the end faces on both sides and then manually measure the light, which can save you a lot of detours. For computer rooms with mixed port types, it is recommended to use the maintenance window to conduct an end face survey and replace jumpers with inconsistent grinding styles with the same style at once.

Three habits to avoid mixing

First, when receiving the goods, sort them according to the color of the dust caps and affix category labels; second, the ODF port table indicates the grinding type of the adapter in each port. Check them one by one before the renovation. Old equipment with FC interfaces can be used.LC-FC single mode dual core jumperMake transitional connections; third, try to keep only one grinding system in the same computer room. If mixed modification is really needed, first prepare the conversion plan and jumper list before proceeding, and do not rely on temporary test plugging on site. The adapters listed on the EB-LINK site are marked according to UPC and APC classification. If you are not sure about the end configuration of the existing links, you can send the port list to 0755-83179002 and ask technical support for help to check.