I've tried to use internal clock from 2408 and set QS7 to get external 48kHz from BNC word clock. It happens to have two issues:

1. When I use Cue Mix to get no latency monitor, I always lose the channel 1 for sync signal. Is that normal? If so, is there any work around to get away with it?

2. The direct sound from QS7 via optical does NOT always work. I saw the input signal from the front panel of 2408, but no output light 's blinking at all. So, keep clicking the REFLESH button to make sure that everything is in the right state. On the good day, it works fine after clicking a couple times. On the bad day, it's just silence, one left channel, or one left channel with some noise in the right channel. I'm not sure if my 2408 is defective, or because I'm using it with PC which may not be enough reliable. However, standalone mode (w/o PC) works fine every time.