What is the main characteristic of a launch cable in a fiber optic test setup?

The main characteristic of a launch cable in a fiber optic test setup is that it transmits light from the source. Launch cables are specifically designed to connect a light source, such as a laser or LED, to a fiber optic tester and serve as the initial segment of the optical path. This setup is crucial for performing tests on multimode and single-mode fibers. By transmitting light from the source into the fiber, the launch cable enables the assessment of the fiber's performance, including attenuation and signal integrity.

The use of a launch cable allows for effective testing of the fiber and helps ensure accurate measurements by providing a known light input into the system. This characteristic is vital in determining the quality and parameters of the fiber optic link being tested, aiding in the installation and maintenance of fiber optic networks.