The OTDR launch cable connects the OTDR to a link-under-test, discloses the insertion loss and reflectance of the near-end connection. This unit has small spool within the “launch box”, which is used to create true conditions for testing another similar optical fiber for faults. Use of this equipment avoids undesirable variations in loss and distance measurements along your installed cable. A launch cable will help to overcome the blind spot or Dead Zone of an OTDR brought about by high launch power or faults near the launch end of the fiber.