Your Garmin c550 StreetPilot GPS device comes with a set of pre-installed maps. Occasionally, road layouts change, so eventually you'll need to download new maps from Garmin to ensure that yours are up to date. Garmin handles map updates via a Garmin Communicator Plugin. Once you've installed the plugin, you can access Garmin's map update Web page to download new maps to your c550 device.
Connect your Garmin c550 StreetPilot to your computer using the PC interface cable that came with the device.
Open your Web browser and navigate to the Garmin Communicator Plugin website at www.garmin.com/communicator.
Click the "Download" button to save the plugin installation file to your computer.
Close all open Web browsers.
Run the downloaded installation file to initiate the Garmin Communicator install wizard.
Click the "Next" button and then check the box next to "I Agree" and click "Next" again. The installation wizard will install the Garmin Communicator Plugin to your computer.
Click the "Done" button to open the Garmin Communicator Plugin test page in your default Web browser. An on-screen message will indicate whether the plugin installed successfully.
Navigate your Web browser to https://my.garmin.com/maps/updates.htm. The Communicator plugin will determine whether there are available updates for your Garmin c550 device.
Follow the on-screen prompts to install available updates to your Garmin c550 StreetPilot.