Overview
The Conexant
CX11656 device is an integrated physical layer transceiver or PHY (Figure 1-1). It is designed to use existing ac electrical wiring within the home as a networking physical medium. The PHY’s robust performance in the electrically noisy power line channel is due to the use of Orthogonal Frequency Division Multiplexing (OFDM). This multi-carrier modulation scheme allows the PHY to dynamically “learn the channel”— data can be shifted from one carrier to another as real time noise and attenuation conditions change. This overcomes the flaw inherent in previous power line networking technologies—as electrical appliances were turned on and off, changing line conditions caused signal quality to become degraded to such an extent that data transmission became impossible. The CX11656’s OFDM technology finds the low noise, low attenuation portions of the spectrum available to it and continues data transmission.

Features
• Single-chip powerline networking controller with IEEE802.3u MII interface
• Implements the HomePlug Powerline Alliance Industry Specification V1.0
• General purpose 7-wire serial PHY data interface
• Selectable MDI/SPI PHY management interface
• Up to 14 Mbps data rate on the powerline
• Orthogonal Frequency Division Multiplexing (OFDM) with patented signal processing techniques for high data reliability in noisy media conditions
• Intelligent channel adaptation maximizes throughput under harsh channel conditions
• Integrated quality-of-service (QoS) features such as prioritized random access, contention-free access, and segment bursting
• 56-bit DES Link Encryption with key management for secure powerline communications
• EEPROM interface for fast access to configuration parameters allows system designs
to leverage standard Ethernet drivers
• 3.3 V signaling, 5 V tolerant interface
• Support for three status LEDs
• 144-pin LQFP package

Applications
• Residential gateways and home routers
• Network home or small office PCs
• Enable no wire installation networking for information appliances
• LAN gaming
• Share DSL or cable modem access
• MDU/MTU applications
• Embedded applications