Taking a look around the machine, Dell has managed to squeeze on most of the connectivity a business user is likely to need when on the move. On the left you'll find a VGA output, a combined eSATA and USB port, the headphone and microphone jacks, a 34mm ExpressCard slot and below this a SmartCard reader that provides secure authentication along with the TPM -- as does the optional fingerprint reader on the main body of the machine.
Then, on the right, there's the Ethernet port, the second USB port, a mini-FireWire, a memory card reader and a wireless radio switch. A power input and lock slot can be found on the back, either side of the battery, while there's a docking port on the bottom for extending this connectivity at the office. Other nice touches include a battery meter on the battery, the small 45W power supply and the fact that the second USB port is powered, so can charge devices even if the notebook itself is powered down.
One area where the E6400 particularly impressed was the keyboard and given the Latitude range has commonality in this respect, the E4200 is also very impressive. Keys have a wonderful tactile feel to them, respond crisply and evenly and flex is barely detectable. No complaint can be made of the layout either with every element logically positioned, including slightly withdrawn cursor keys that are flanked by Page Up and Page Down keys.
Unlike the ThinkPads of this world, the E4200 doesn't have both a trackpoint and touchpad, settling for just the latter. It works just fine, being smooth, well proportioned and serviced by two responsive buttons.
One thing the E4200 does have, however, is an instant-on secondary OS -- something Dell is calling the Latitude ON Reader. This uses a separate Linux sub-system, powered by an ARM processor and flash memory, and gives you access to web browsing, email, calendar, contacts, instant messaging and document viewing. Provided you don't boot into Windows this could potentially offer days, rather than hours, of usage on a single charge.
Much to our irritation, though, our sample (due to its older configuration) doesn't feature it, so we aren't able to give you a full rundown. But, from our time using the ON Reader in the past, it's without doubt a very useful feature for anyone accessing basic functionality on the move -- that'll be most people. Indeed, this alone could tempt many, so it's well worth the relatively minor premium it demands.