We tested the kit with only the two included adapters but, according to TrendNet, up to 16 adapters can work together to create a large powerline network. Note, however, that as the adapter has no power pass-through socket and it's not designed to be used with a power strip, it will occupy one wall power socket. Make sure you have more than one power outlet at the far end of the connection.
There's nothing to setting up a powerline connecting using the TPL-401E2K kit. This process is typical for most, if not all, powerline kits. First you hook one of the adapters to the network via the router (or the hub) using a network cable. The second adapter is connected to an Ethernet-ready device, say, at the far corner of the house. After that, you just plug both adapters into the power sockets. If the two locations share the same electrical wiring, which they do in most homes or apartments, a powerline network connection is now established. This whole process takes just a few minutes, and you can't make a mistake.
The kit also comes with a Windows-based desktop configuration application that allows you to view the connection and perform other tasks on the adapters, such as change its password or update the firmware.
The TrendNet TPL-401E2K's performance was not even close to its theoretical ceiling of 500Mbps, but it's indeed the fastest we've seen in among powerline adapters on the market. The two adapters consistently registered more than 79Mbps, compared with 22.9Mbps of the Netgear XAV2001 and 22.9Mbps of the Plaster Network PLN3. At this speed the TrendNet can finish transmitting 500MB of data in about 50 seconds.
The kit comes with a power-saving feature that automatically turns off the adapter when the connection is idle. This is overall a good feature, but it can cause temporary disconnections; we found that at times, the adapter wasn't powered back on fast enough when the connection was needed.
(Longer bars indicate better performance)
Service and support
TrendNet backs the TPL-401E2K kit with a three-year warranty, which is much longer than what other powerline kits usually come with. Though don't think you'll need much support for the adapter, on the company's Web site, you'll find lots of support information, including troubleshooting, a knowledge base, and firmware, software, and manual downloads. The company also has 24-7 free phone tech support.