To synchronize a CueServer show with an external running time of a show (typically found in video or theme park productions), you'll want to provide a timecode input to CueServer.
CueServer natively accepts and processes MIDI Timecode (MTC). If you want to use SMPTE Timecode instead, you have to convert the Analog SMPTE signal to a Digital MTC signal. We have recommended (and many customers have successfully used) the simple and reliable JL Cooper PPS-2 SMPTE to MTC converter.
There are other solutions on the market as well, however we're just familiar with this relatively simple solution for getting SMPTE into a CueServer.