The Mio C320 is equipped with a 20-channel SiRFIII GPS chip and comes preloaded with TeleAtlas maps of the United States, Hawaii, and Puerto Rico. You can start planning a trip by entering a specific address, picking a POI, selecting a destination from your My Favorites or recent destinations list; or you can tap a point on the map and hitting the Route To option. The system can create directions by fastest, shortest, or most economical route; with or without toll roads, highways, U-turns, and so forth; and in various modes, including car, bicycle, and pedestrian.
The C320 supports multistop routes, and there's a database of 1.7 million POI. The number of included POI is a bit disappointing, since even the entry-level Mio C230 offers more entries at 3.5 million while the C520 contains 6 million POI. That said, you get all the major categories--gas stations, ATMs, lodging, and restaurants--as well as more specialized interests, such as concert halls and amusement parks.
Maps are presented in 2D or 3D mode, and there's a Night Mode option that automatically changes the maps colors for better visibility at night. You also have your choice of viewing a full-screen map or a split-screen view. The latter displays various details about your trip. You can cycle through several views that give you the distance and direction of your next turn; a list of upcoming turns; nearby gas stations; current time; estimated time of arrival; speed; and more.
Navigation guidance comes by way of text- and voice-guided turn-by-turn directions. Unfortunately, unlike the Mio C230, the C320 doesn't support text-to-speech functionality, which is a disappointment. You can view a detailed list of instructions before you head out under Itinerary or get a running demo of the route with the Fly Over function. If you want to steer clear of a certain portion of the route because you happen to know there's road construction or heavy traffic, just hit the Avoid button and choose from a list of options. The system also supports automatic route recalculations and has a number of safety options, including speeding alerts, a screen lock that prevents you from using the touch screen when the car is in motion, and safety camera information. The C320 doesn't ship with traffic capabilities out of the box, but you can add this function with an optional traffic receiver. Finally, the system comes with a music player that supports MP3 files. The player is basic but includes equalizer settings and allows for playlist creation.
We tested the Mio C320 in San Francisco, and from a cold start, it took the unit about 3 minutes for satellite acquisition under clear skies, while subsequent starts were almost instantaneous. On unspecified trips, the C320 did a good job of tracking our location and only lost a signal when we drove through the Broadway Tunnel.
We also entered our standard trip from the Marina District to CNET's downtown headquarters. Route calculation was swift, and we checked the trip itinerary and agreed with the prescribed route. Once on the road, we found the voice directions to be clear and loud enough, and you can set the system to alert you to upcoming turns with a chime. While this is handy, what we really missed is the text-to-speech functionality. Finally, we missed several turns to test the C320's route recalculation rate, which was quick and accurate.
Music playback sounded pretty decent through the system's speakers, with plenty of volume and good balance. It's too bad the player is only limited to MP3s. The C320's lithium ion battery is rated for up to 5 hours of use.