TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Lab 3 – Differential Pair Synchronous communication (Physical Layer) Semester B, 2010 MPC8360 Computer Networks I

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc The Open System Interconnection Reference Model (OSI) Physical Data Link Network Transport Session Presentation Application We Are Still Here

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Noise ► So far we have considered only noiseless channels. ► This is obviously not the case in real life channels in which noise is always present. ► Noise is a random fluctuation in an electrical signal, it cannot be predicted.

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Noisy Channel Transmitter Noisy Channel Receiver 0 V -2 V 2 V Logic 0 Logic 1 0 V -2 V 2 V Logic 0 Logic 1 Data Data + Noise

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Wire A Some Sources of Noise ► Thermal noise Present due to the motion of the molecules in the conductor. ► Crosstalk Caused by inductive/capacitive coupling between two wires that are close to each other. Wire B 0 V 5 V Logic 1 Logic 0 bit flipped due to crosstalk

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Differential Pair ► A method of transmitting information electrically by means of two complementary signals sent on two separate wires. Transmitter Noisy Channel Receiver Data - Data Data + Noise - Data + Noise A BB A 0.5 [ A – B ] = 0.5 [ ( Data + Noise ) – ( – Data + Noise ) ] = 0.5 [ Data + Noise + Data – Noise ] = 0.5 [ 2 (Data) ] = Data 0 V -2 V 2 V Logic 1 0 V -2 V 2 V Logic 0 Assuming the Noise is equal in both channels

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Making the Noise equal Noise Source Blue wire receives most of the noise Both wires receive the same amount of noise Twisted Pair

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc USB - Universal Serial Bus ► The USB standard defines several physical interfaces ► USB signals are transmitted on a Twisted-Pair data cable ► The USB Standard was designed to transfer data & power.

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Ethernet ► Ethernet is a family of frame-based computer networking technologies for local area networks (LANs). ► It defines a number of wiring and signaling standards for the Physical Layer and Data Link Layer of the OSI networking model. ► Ethernet is standardized as IEEE ► Ethernet is the most widespread wired LAN technology

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Ethernet physical layer ► The Ethernet standard defines several physical interfaces depending on the connection speed and/or distance. ► RJ 45 Connector ► Unshielded Twisted Pair (UTP) ► Shielded Twisted Pair (STP or STP-A) ► Category 3 (cat3) Mbit/s Category 5 (cat5) Mbit/s Category 5 (cat5) Category 3 (cat3)

TM Freescale Confidential Proprietary Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc Quick Overview