The Motorola 10BASET transceiver, designed to comply with the ISO 88023 [IEEE 802.3] 10BASET specification, will support a Medium Dependent Interface (MDI) in an embedded Media Attachment Unit (MAU)*. The interface supporting the Data Terminal Equipment (DTE) is TTL, CMOS, and raised ECL compatible, and the interface to the Twisted Pair (TP) media is supported through standard 10BASET filters and transformers. Differential data intended for the TP media is provided a 50 ns preemphasis and data at the TP receiver is screened by Smart Squelch circuitry for specific threshold, pulse width, and sequence requirements. Other features of the MC34055 include: Collision and Jabber detection status outputs, select mode pins for forcing Loop Back and FullDuplex operation, a Signal Quality Error pin for testing the collision detect circuitry without affecting the TP output, and a LED driver for Link Integrity status. An onchip oscillator, capable of receiving a clock input or operating under crystal control, is also provided for internal timing and driving a buffered clock output.