The TH8056 is a physical layer device for a single wire data link capable of operating with various CSMA/CR protocols such as the Bosch Controller Area Network (CAN) version 2.0. This serial data link network is intended for use in applications where a high data rate is not required and a lower data rate can achieve cost reductions in both the physical media components and the microprocessor and/or dedicated logic devices that use the network. The network shall be able to operate in either the normal data rate mode or the high-speed data download mode for assembly line and service data transfer operations. The high-speed mode is only intended to be operational when the bus is attached to an off-board service node. This node shall provide temporary bus electrical loads which facilitate higher speed operation.