User controls are positioned to the right of the display and include View, Locate, Option, Enter, and Cancel buttons. There's an eight-way rocker switch for scrolling through menu items and selecting characters using the onscreen keyboard, as well as two buttons for zooming in/out of maps. Around back on the upper bezel sits a flip-up antenna, while USB and power jacks are on the left side of the unit. Unfortunately, the RoadMate 300 suffers from a couple of design glitches. The SD card slot is located on the bottom of the unit, which makes it difficult to change cards without repositioning the system. Also, we were disappointed by the lack of a physical volume control (volume is controlled in the User Options menu), but we did like the addition of a headphone jack on the right side. The windshield-mounting arm is a thing of beauty; it connects to your windshield via a suction cup and is one of the sturdiest mounts we've seen. With a simple twist of the locking dial, the suction cup is firmly seated or released. In addition to the mapping software and mounting arm, the RoadMate 300 ships with a 12-volt vehicle adapter, an AC power adapter, a USB cable, and a documentation CD. A remote control would have been nice, however.The Magellan RoadMate 300 contains a 14-channel GPS receiver; 2 of these channels are dedicated to the Wide Area Augmentation System (WAAS), which uses a system of satellites and ground stations to provide GPS signal corrections and thus improve accuracy. It has 110MB of internal memory, 30MB of which are used by preloaded base maps (major roads and highways) of the 48 contiguous U.S. states, Hawaii, Canada, and Puerto Rico. Unlike the Cobra NavOne 3000, the RoadMate 300 does not include a hard drive, so detailed maps must be uploaded from a PC using the included Magellan RoadMate Manager software and a USB cable or by purchasing preloaded regional SD cards for $49.99 each. Regional SD card maps include street-level detail and points of interest (POI) for an entire region, such as the West Coast, Northeast, Midwest, and so on. RoadMate Manager is a user-friendly application that allows you to select a region and save it on your PC's hard drive or upload it to the RoadMate 300, but it can be time consuming, especially if you are planning a big trip. It tells you the size of the map file you are saving and how much memory is available on the RoadMate for uploading. We created a map of the Northeast corridor (I-95) from Boston to Philadelphia that required 79MB of memory and took 16 minutes to upload. The software also lets you plan trips, manage your personal settings and address book, and replay trip tracks from your RoadMate 300.
Other features include voice- and text-guided driving directions; the ability to create multiple destination points in a single route; the ability to create routes using several criteria such as addresses, POI, business names, and intersections; a trip computer; and status screens that display speed, heading, and current location. The Auto Reroute function will calculate a new route if you veer off course or miss a turn, and the Route Exclusion feature provides a quick way to find an alternate route if you know a certain road is closed or clogged with traffic.Magellan has always produced accurate GPS products, and the RoadMate 300 is no exception. The first time we fired it up, we had to wait for close to five minutes for the unit to obtain a 3D fix (four satellites), which was longer than we expected but not unreasonable. Subsequent start-up times were typically 5 to 10 seconds. We maintained a strong lock throughout our drive from Long Island to Manhattan, losing reception only when we hit the Midtown tunnel (which is normal) and for a brief moment down near the Wall Street area. Our position on the map was spot-on, and the driving directions were flawless. The RoadMate handled an unplanned detour off the Expressway without skipping a beat, guiding us safely through unfamiliar territory and back onto the main road.