The Realtek RTL8221B(I)-VB-CG (hereafter referred to as the RTL8221B(I)-VB, except where differences exist) is a highly integrated Ethernet PHY transceiver that is compatible with 10BASE-Te, 100BASE-TX, 1000BASE-T, and 2.5GBASE-T, and is fully compatible with both the IEEE 802.3 standard and the NBASE-T™ Alliance PHY. It provides all the necessary physical layer functions to transmit and receive Ethernet packets over CAT.5e UTP cable.
The RTL8221B(I)-VB uses state-of-the-art DSP technology and Analog Front End (AFE) to enable high-speed data transmission and reception over UTP cable. Functions such as Crossover Detection & Auto-Correction, polarity correction, MDI swap, adaptive equalization, cross-talk cancellation, echo cancellation, timing recovery, RFI protection, thermal management, loopback diagnostic capability, and error correction are implemented in the RTL8221B(I)-VB to provide robust transmission and reception capabilities.
Data transfer between MAC and PHY is via the SERDES (Serializer-Deserializer) interface, which supports SGMII, HiSGMII, and 2500Base-X. The RTL8221B(I)-VB operates at various digital I/O voltages, including 3.3V and 1.8V.