 "Communications with M520"
What method are you using to communicate, RS232? How is your cable wired dtc or dce? What are you using on your PC to initiate communications? Can you describe what is or isn't happening? If you are try to communicate with RS232, the most common problems are: 1) cable problem - know how it's wired and set appropriate params on both sides. (do you have a null modem adaptor because this might be needed 2) baud/flow control problems - all settings for speed and signalling MUST be compatible (especially the speed) You can troubleshoot your setup with a serial breakout box. | 
