Design Team 7
Mark Jones
Sedat Gur
Ahmed Alsinan
Brian Schulte
Andy Christopherson

Introduction

Ethernet History and Structure

Time Domain Reflectometry

Active Link Cable Diagnostics

Digital Spectrum Analysis

Power-over-Ethernet Detect

Output Data

History of Ethernet

Computer based networking technology for Local Area Networks (LANs)
 Developed by Xerox in Early 70’s
 Used for approximately 85% of world’s
LAN-connected PCs and workstations

Implemented with multiple types of cable
 Coaxial
 Twisted Pair
 Fiber Optic

Twisted Pair Wires

Used in many Ethernet and telephone systems

Receiver takes the difference between the wire pair

Any interference in signal will be canceled out

Advantages
 Cables are thin, easy to run throughout building
 Flexible
 Cheap to manufacture

Disadvantages
 Resistance to electromagnetic interference depends on pair twisting scheme used

Twisted Pair Standards

Category 3
 Up to 10 Mbps
 Bandwidth up to 16 MHz
 Popular in early 90’s

Category 5
 Used for mainly 100Mbps networks
 Bandwidth up to 100Mhz

Category 5e
 Enhanced version of Category 5
 More rigorous standards

Recommended for most networks

Category 6
 Bandwidth up to 250MHz

Recommended for gigabit speeds

So what kind of errors are we looking for?

Opens and Shorts

Cable impedance mismatch

Bad connectors

Terminations mismatches

Water damage

Any other discontinuities

Also can find cable length

Time Domain Reflectometry

Will diagnose opens, shorts, cable impedance mismatch, bad connectors, termination mismatches, etc.

Uses reflections to find these errors and their locations

Time Domain Reflectometry

Pulse is transmitted of known amplitude down twisted pairs

Reflects off imperfections and faults

Measure return time and amplitude of reflections

Time Domain Reflectometry

With the gathered data we can find
 Distance and Magnitude (Impedance)
 Non-terminated Cables (Opens and Shorts)
 Discontinuities (Bad Connectors)
 Improperly Terminated Cables

Time Domain Reflectometry

Active Link Cable Diagnostics

Use of passive digital signal processing
 Will find cable length with active cable

Uses predefined parameters based on the cable properties
 High accuracy cable length

Spectrum Analysis

Analog Spectrum Analysis
 Uses a variable band-pass filter

Digital Spectrum Analysis
 Uses Discrete Fourier Transform

Results in frequency spectrum of our signal

Digital Spectrum Analysis

Gives magnitude of the frequency response
 This will show us how the signal is spread out along the frequency spectrum
 Allow us to see noise along the line

Especially how it relates to the length of the cable

Power-over-Ethernet Detect

Power can run over 2 pairs of wires while data is on the remaining 2 pairs

Power is supplied by a PSE and received by the
PD.
 42~57 Volts

Power-over-Ethernet Detect

Detection Level can be varied as well as
Turn-on and Turn-off voltages

PHY to MAC Communication

PHY Layer
 Transmission of raw bits, not logical data

MAC Layer
 Logical communication

PHY to MAC Communication

Microcontroller (MCU)
 Able to communicate with PHY layer

Uses Media Independent Interface (MII)

Readable Interface

Microcontroller can be programmed to send data to
 LCD Display
 Computer
 LEDs

PHY to YOU

Conclusion

Ethernet History and Structure

Time Domain Reflectometry

Active Link Cable Diagnostics

Digital Spectrum Analysis

Power-over-Ethernet Detect

Output Data

QUESTIONS?