As part of their broad eHome initiative, this April at the Windows Hardware Engineering Conference (WinHEC) 2002 in Seattle, WA, Microsoft showed the new iTran IT800 power line modems ( in their booth with a preliminary development version of their Simple Control Protocol (SCP) stack loaded, which allows SCP-enabled devices in the house to be monitored and controlled via the power lines (the two boxes with the yellow/green covers).

They also demoed a technology preview version of their SCP to Universal Plug and Play (UPnP) bridging software running under Windows XP. For the demonstration, they had a specialized slider (the white plate next to the mouse) mounted in a J-Box which connected through a customized kind of mouse interface (the black box on top of the modems). This device acted like an in-wall light dimmer slider. It communicated through the Serial Peripheral Interface (SPI) on one of the power line modems that was connected to the Windows XP computer.

Acoustics First
This IT800 had lamp controller device software loaded into it?s EEPROM for controlling the lamp (just like a normal light dimmer would). For the controlled lamp, they had a standard light bulb (the white square tower on the right side of the picture behind the arm) connected to a modified version of one of those outside light-based lamp controllers used for automatically turning the lights on at dusk and off at dawn. One end of a custom PIC Micro Controller Unit (MCU) ? this is the board on the red mat with the wires coming out – had the output connected to the place where the photocell used to be on the lamp controller (the hard part was coming up with a way to dim the light through the original photocell interface). The other side of the PIC connected to the SPI on a second stand-alone IT800 that used the power line to communicate bi-directionally to the computer-based modem mentioned earlier. Naturally, the data was encrypted to prevent wire snooping.

On the computer screen, you can see the lights that were discovered automatically through UPnP (via the bridge) and show up as objects in My Network Places under Windows XP. In addition, you can see the SCP Property Route Tool running (which allows one to make logical connections between the properties of controller and controlled services within devices) and a couple of software-based lamp controllers that also had routes configured to the slider and lamp (via the Property Route Tool).

It actually worked pretty well and gave a great glimpse into the future of totally integrated home control networking. Microsoft ultimately plans to incorporate the iTran/SCP chips for slow speed (about 7.5 Kb/s) power line communications into a USB-based dongle and provide supporting software as part of their UPnP-based infrastructure under Windows XP (and especially later in Longhorn). They eventually will release a version of their UPnP to SCP bridge software that will allow SCP-based devices to be queried and controlled through something like a UPnP-enabled version of their new Freestyle remote control-based user interface running on a TV.

All in all, it was kludged up and customized a bit, but still pretty cool. Reliable and secure power line-based interactive control that integrates with UPnP and the rest of the electronic devices in the home finally may become a reality!

Derek R. Flickinger is Vice President of Research and Development for Interactive Homes, Inc., a consulting, design, implementation, and development company focused on delivering standards-based Distributed Audio, Video, Communications, and Control (DAVCC) services in the home. His long-term goal is to be instrumental in the development and deployment of DAVCC-based services on space stations. He can be reached at .