I whipped up this little utility a while back as a quick and easy way to get screen captures from the TDS3000 series’s serial port.
Download it here.
Choice of serial cable
Note that if you are building your own Null-Modem serial cable to connect to the scope, please connect all signals as per standard Null Modem cable wiring. This program requires hardware flow control. It is not sufficient to connect only the RX and TX lines.