Intel(R) Wireless WiFi Link 4965AGN
other one
Intel(R) Wireless WiFi Link 5100AGN
You should note that the router (DIR-615) is a 2.4Ghz only radio broadcasting router (is this the true model you have?)
Both the Intel WiFi adapters are in the Intel Centrino product range. Sometimes, you may require the Intel "management" software in order to get the laptops to connect to the router. It seems that often, the Wireless Zero Configuration (WZC) system. will fail to see the router's wireless "signals." The router SSID will just not show up in the WZC "Available networks..." list.
Also, it needs to be noted that the forum "sticky" note on the 300Mbps speed access is completely true. These Intel Centrino wireless adapter may only get 130Mbps wireless N speeds. In order to get the faster speeds, you will require a router that will do the 5.0Ghz radio frequency.