Tek Scope Screen Capture

I've been taking scope pictures with my phone, but sometimes the pictures do not have good focus and the picture size is large.    The Tek scope has a serial port which commands and data can be sent and received.  But I have had a lot trouble to get the Tek's own software to work.   For screen capture, it is actually a lot simpler: just set up the hardcopy to output to RS232 and choose a format such as PNG, then just hit the hardcopy button, the data come out on the serial port.  Now it is just a matter of capturing it on the PC, which can be a simple Python script using pyserial.   A null modem cable is necessary; the maximum baud rate is 38400.  It takes about 3-4 seconds to get the screen shot, which is much better than you can capture with your phone.