The optical ports are labeled on the top of the units.
Both the master and remote have an optical power meter port labeled OPM located on the right-hand side. The OPM port is a universal port, with two adapter caps that come with each unit – a 2.5mm adapter cap allows connection to SC, ST, and FC connectors, and a 1.25mm cap allows connections to LC connectors.
The source port located on the left-hand side determines what type of fiber the units can test. There are three different source options. MM indicates dual-wavelength multimode 850 and 1300nm, SM indicates dual-wavelength 1310 and 1550nm, and VFL indicates visual fault locator.
The units come in either single-source or dual-source configurations. Single-source units are either multimode only or singlemode only, and come with a SC light source connector port.
Dual-source units have 3 combinations: MM and SM; MM and VFL; or SM and VFL. Dual-source units come configured with LC light source ports.