GARMIN PC Interface Cable - RS232 Serial Port Connector-eTrex H, eTrex Legend, eTrex Vista, eTrex Venture, eTrex Summit, Geko 301,201 and Gigaware serial to USB PC interface cable. $20 for both.
https://buy.garmin.com/en-US/US/sho.../pc-interface-cable/prod654_010-10206-00.html
https://buy.garmin.com/en-US/US/sho.../pc-interface-cable/prod654_010-10206-00.html