资 源 简 介
The NE8392C Coaxial Transceiver Interface (CTI) is a bipolar coaxial line driver/receiver for Ethernet (10base5) and Thin Ethernet (10base2) local area networks. The CTI is connected between thecoaxial cable and the Data Terminal Equipment (DTE) and consistsof a receiver, transmitter, receive-mode collision detector, heartbeatgenerator and jabber TImer (see Block Diagram). The transmitteroutput connects directly to a doubly terminated 50W cable, while thereceiver output, collision detector output and transmitter input areconnected to the DTE through isolaTIon transformers. Isolationbetween the CTI and the DTE is an IEEE 802.3 requirement thatcan be met on signal lines by using a set of pulse transformersnormally available in a standard 16-pin DIP. Power isolation for theCTI is achieved using DC-to-DC conversion through a powertransformer (see Figure 1, Connection Diagram).During transmission the jabber timer is initiated to disable the CTItransmitter in the event of a longer than legal length data packet.Receive-mode collision detection circuitry monitors the signals onthe coaxial cable to determine the presence of colliding packets andsignals the DTE in the event of a collision. At the end of every transmission the heartbeat generator creates a pseudo collision for a short time to ensure that the collision circuitry is functioning correctly. The heartbeat function can be disabled for repeater applications.
