I have linked ICON and Smarthome Lamplincs and Keypadlincs to my EZSrve. What Smarthome devices have you not been able to use? When you added those devices to EZSrve, was the link established successfully?

Access Points serve two purposes. They provide the RF send/receive capability for wireless devices such as the Remotelinc and the Thermostat Adaptor. The more Access Points you have, the larger the RF coverage area. The second function of Access Points is to provide cross phase communication. Insteon messages on one power line phase are repeated on the other power line phase via the RF capability of the Access Point. For this to work there has to be an Access Point plugged into a receptacle on both power line phases. If the three Access Points are powered from the same power line phase, it is as though you had no Access Points as far as phase coupling is concerned.

The more Insteon devices you add, the better things tend to get because each Insteon device repeats messages. I’m thinking the benefit you gained by adding an Access Point near the computers was the result of that repeating, not from RF coupling (assuming that 3rd access point did not establish the coupling). Plugging in a LampLinc or ApplianceLinc might have provided the same gain. I would think about installing a FilterLinc between the computer(s) and the power line. Computer power supplies (and some TVs and UPSs as well) want to keep noise to minimum and act as signal suckers. Don’t like that term but it seems to be what folks use to describe the condition. I’ve installed a FilterLinc on each of my computers/UPS installed in different locations in the house and it has helped. You can unplug the TVs, computers and UPSs you don’t need to test Insteon (not just turn them off) and see if that helps. If so, then they need a FilterLinc. As an FYI, when you save a Scene you are linking devices.