In our case, we paired all three lines to the LG Prada, the T-Mobile Sidekick 3, and the Samsung SPH-M510 to Line 1, Line 2, and Line 3, respectively. We managed to make, receive, and end calls with our regular desk telephone without any problems. As long as all three cell phones are in range, incoming calls to all phones will route to the one desk telephone we used. The Xlink will always use the lowest line number by default for outgoing calls, so in our case, all outgoing calls were made via the LG Prada's line. If you want to make outgoing calls via another cellular line instead, you have to dial the corresponding line number, then hit the "Flash" key on the telephone. However, if any of the cell phones are not within range of the Xlink (it has a range of about 50 feet), a rapid series of beeps will sound, indicating that the line is not available for outgoing calls.
So how do you know which cell phone an incoming call is from? Well, each line on the Xlink has a distinctive ring pattern, meaning an incoming call on Line 1 will sound different than an incoming call on Line 2. The appropriate blue light will also pulse differently depending on the line. Also, should you tire of using the Xlink in the middle of a call, you can press the appropriate line button and it'll disconnect the Xlink to the cell phone, and the audio will transfer automatically to your cell phone.
Other features of the Xlink include caller ID display and support for speed-dialing, voice mail, call waiting, and voice dialing--all from your standard desk telephone. Overall, we think it is excellent value for the money if you like the convenience of a cell phone but prefer the comfort and security of using a normal telephone. The value is especially noticeable when using it with a cordless phone, since you can just park your cell phone in the location with the best signal, then use the cordless phone around the house. Do note however, that Bluetooth signals sometimes interfere with Wi-Fi or 2.5Ghz cordless signals, so try to keep your devices far enough from each other. We tried ours with a 900Mhz cordless signal, and everything worked just fine.