Am7996

The Am7996 IEEE 802.3/Ethernet/Cheapernet Trans-ceiver supports Ethernet Version 2, IEEE 802.3 10BASE-5 and IEEE 802.3 10BASE-2-Cheapernet) transceiver applications. Transmit, receive, and colli-sion detect functions at the coaxial media interface to the data terminal equipment (DTE) are all performed by this single device.

In an IEEE 802.3 (10BASE-5)/Ethernet application, the Am7996 interfaces the coaxial (0.4+  diameter) media to the DTE through an isolating pulse transformer and the 78 W attachment unit interface (AUI) cable. In IEEE 802.3 10BASE-2-Cheapernet applications, the Am7996 typi-cally resides inside the DTE with its signals to the DTE iso-lated and the coaxial (0.2+  diameter) media directlyconnected to the DTE. Transceiver power and ground in both applications are isolated from that of the DTE.

The Am7996's tap driver provides controlled skew and current drive for data signaling onto the media. The jabber controller prevents the node from transmitting exces-sively. While transmitting, collisions on the media are de-tected if one or more additional stations are transmitting.

The Am7996 features an optional SQE Test function that provides a signal on the Cl pair at the end of every transmission. The SQE Test indicates the operational status of the Cl pair to the DTE. It can also serve as an acknowledgment to the node that packet transmission onto the coax was completed.