7455 is a fail-safe, bypass protection switch for critical digital paths for broadcast or satellite applications. When a fault is detected in the primary input, and the secondary input is verified as good, the switch will activate, causing the secondary input to be switched to the module's output. It includes a passive, fail-safe path that ensures there is an output even in the event of a total power failure. It supports SD SDI, HD SDI, SMPTE 310M and DVB-ASI signals. Different types of signal testing (vetting) can be enabled on the 7455 and it will apply the tests according to the type of input that is present. This happens automatically and independently for the primary and secondary inputs. This means that the primary input of the module could be HD SDI while the secondary input is SD SDI. It is also possible to mix SDI, ASI and 310 signals, or receive the same standard on both the primary and secondary inputs. The health of a high definition or standard definition video signal is determined by monitoring crucial parameters in order of increasing complexity. Timing reference signal (TRS), or a persistent loss of digital sync is tested first. Black, embedded audio and freeze are also evaluated. Each test can be configured by the user.