This plugin controls from Cisco SIP Phones.
If you don't know the Cisco IP Phones, they come in different flavors. The 7971GE has a color touch screen and runs about at US$200. Probably one of the cheapest HA Touchscreen controllers you can get considering that you get a great SIP phone thrown in.
There are also other model like the Cisco 7961GE at about US$100 with the same functionality minus the touchscreen and color.
Just unzip and put into the plugin directory. The plugin directory name needs to be "CiscoServices"
To make the plugin work with the phones, the Cisco Phone Config (SEPXXXXXX.xml.cnf) needs to have the INDIGO server URL configured:
For convenience, action groups whose name is prefixed with "_cphone._" (For example 'cphone.Turn on Lights') will show up in the main menu as well as some sort of shortcut to often used Devices, Actions.
The Device menu actually shows the state of the fixture or switch as well using the pre-installed graphics (Thanks Matt!)