[FieldTrip] problem in reading trigger

[wan amirah Wan azlan]

Dear Fieldtrip user,

I am doing realtime eeg processing via tmsi porti amplifier. My problem is my trigger not able be recognized. 
I am using the following command,

cfg=[ ];
cfg.dataset='buffer://localhost:1972';
cfg.trialdef.eventtype='?';
cfg=ft_definetrial(cfg);

'no events were found in the datafile' is shown in matlab command window. Why does this happen?

Thanks.
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