Vicipn

Hi, good evening.
I´ve connected a tektronix osciloscope over USB connections (DPO4104 and TDS2012B), I need to export data by the two channels of the TDS 2012B and, when connect the DPO4104 I need get data for the 4channels but I can´t do it. I select the readwaveform function but I don´t know how call all chanles my question is: How can I call two or more channels in the readwaveform function? I´ve been trying this:
Input argumnet(s): 'channel1', 'channel2', 'channel3', 'channel4'.
I hope that you can help me, I´ll wait your response. Thanks for all.
Professional Interests: aquering data over tmtool