Explanation...

The diagram to the left shows a typical two-way HFC Cable installation.

Two-way HFC Cable

IES determined that an alternative was needed for load management and AMR capabilities over HFC cable. IES developed a gateway that uses a narrowband channel on two-way HFC cable to communicate. This gateway only uses a 25 kHz channel while a cable modem uses 6 MHz. While a 25 kHz channel only supports 2400 baud, that speed is all that is required for AMR and load control. An on-demand read of a gateway can be completed in less than 2 seconds. A broadcast load control message from the server software to every gateway can be completed in less than 1 second. The IES system does not preclude using cable modems for some applications. In fact, the IES system uses IP for advanced applications. However, it does provide a cost effective alternative for the majority of meter reading applications where only limited communications are required.

The above diagram shows a residential application of automated meter reading and load management using narrowband over a two-way HFC cable system. A gateway is installed on the home next to the electric meter. An AMR-ready electric meter is retrofitted with the IES pulse initiator that provides a pulse output and 12 VDC power to the gateway. The gateway also can connect to gas and water meters via pulse or encoder interfaces. The gateway is connected to the two-way cable system via a coaxial splitter. The gateway contains three pilot relays for controlling central air conditioners, water heaters, or even a cable TV disconnect device. For water heater control, a power relay must be installed at the water heater and connected to the gateway pilot relay.

The IES C3ICable gateways connect to the HFC cable system via a coaxial connection. At the residence, a splitter is installed to split the signal going into the home. A modulator/demodulator is installed in the cable head-end. It modulates a signal on an assigned downstream frequency below 750 MHz. The bandwidth used is less than 25 kHz. The return signal is modulator by the C3ICable gateway at a frequency less than 50 MHz. This signal is also less than 25 kHz.