The CSO Clean Switch Option Software for HCO-3901 from Miranda allows the HCO-3901 change-over routing card to make a glitch-free switch between its two primary inputs which have the same format. An external reference or URS is required to run this software. In this mode, the reference presence is always reported, regardless of the user's setting. The Clean Switch option allows you to do a clean video switch between two synchronized sources. Switching is executed on the proper vertical blanking interval video line according to the format of the reference source.
The switch is free of any glitches, assuming the switch is not due to loss of video or CRC errors and format or reference mismatch are detected. During a switch, the CSO performs a fade out/fade in audio switch on 200 samples to prevent any pops or clicks (only applicable to PCM audio). If there are no errors on input 1 but a reference mismatch is detected on input 2, the CSO keeps working. The Options panel on the HCO-3901 gives some information about obtaining the Clean Switch option, and provides a data entry box "Enter Key" where the activation key supplied when the option is purchased can be entered.