OTDR tests demonstrate that the OTDR can be used to determine loss and length of installed LAN fiber optic cables as well.  OTDR test results can be more reliable than using a power meter but usually consume more time and a higher level of skill. Unfortunately, the OTDR doesn't have the ability to test according to accepted fiber loss test standards nor can it commission a LAN link according to established communications protocols, which competitors of the OTDR such as CertiFiber test tool can do.