Comms over power cables firm launches first chip

Swindon-based data-over-mains firm SiConnect has announced its first chip.

Due to sample later this year, the PLT050 includes all the protocol processing required to establish a bi-directional link over the mains for Ethernet, USB1.1, or 8-bit parallel data.

SiConnect has developed its own synchronous multiple access contention resolution (SMA/CR) protocol, called Poem, which it claims allows smaller chips compared with the OFDM used by some competitors. “Poem protocols are actually quite elegant and are consequently easier to implement in silicon,” company v-p marketing Robert Stead told EW.

It uses four carriers within the 3-30MHz generally allocated for data-over-mains applications. “OFDM puts carriers right across that band. We analyse the network and place specific carriers in the best places and load with data according to ability,” claimed Stead.

Two of the carriers are set when the equipment is made and two are dynamically assigned during operation after interfering signals are located.

Initial applications, according to Stead, will be in devices little bigger than a conventional mains plug. These will have an RJ-45 connector on the back and will provide virtual point-to-point or mesh Ethernet connections around a dwelling or office.

The protocol is such that all nodes have knowledge of every route set up in the mesh, and that any node can act as a repeater for communication between two other nodes.

Poem nodes are registered in the system by simultaneously pushing a button on the back of an existing and a new node. Configuration is entirely automatic, although it can be modified through custom software running on any network-attached PC.

Data-over-mains installations have been accused of radiating excessive RF noise.

“Radiated emissions [from Poem] have been measured explicitly in a real-world house and are within EN55022. We do not emit sufficient RF to be an issue,” said Stead. “It is quite common for competitor’s designs to work with FCC levels which are higher. This is why we have a repeater mode.”

SiConnect said first-generation products will be used to distribute data, voice and video, with Poem chips being built into products such as rear speakers for home theatres in the second-generation.

Different quality-of-service levels can be set for data, with a maximum time delay of 10ms possible. PLT050 operating current is 500mW.

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