Ethernet to phase shift key converter

Details Ethernet to phase shift key converter Ethernet to phase shift key converter

1998-10-30

2003-04-29

Cangialosi, Salvatore (Department: 2661)

Multiplex communications

Pathfinding or routing

Switching a message which includes an address header

C370S425000

Reexamination Certificate

active

06556581

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
The invention relates to the field of networking home computer systems, and more particularly, to a method and system for providing 10BASE-T Ethernet compatible data communications between computers and peripherals in a home environment over an single “twisted-pair” phone line that does not conflict with other signals, such as Plain Old Telephone Service (POTS) or Digital Subscriber Line (XDSL) signals, that may be transmitted simultaneously over the same phone line.
DESCRIPTION OF RELATED ART
As more appliances and items in the home become computer controlled and as more homes obtain multiple computer systems, such as one for the “home office” and one for the family, the importance of having a home network system to allow data communications between the various computer systems and peripherals within a home is ever increasing.
Baseband Ethernet technology is currently being used by many businesses for data interconnection between computers. One such commonly-used baseband Ethernet technology is the 10BASE-T network. The 10BASE-T network has an operating rate of 10 Mbps, utilizes the Carrier Sense Multiple Access/Collision Detect (CSMA/CD) access protocol, baseband signaling and Manchester data encoding.
A standard 10BASE-T Network Interface Card (NIC) is typically used in the construction of a 10 Mbps Ethernet Local Area Networks (LANs) utilizing unshielded twisted-pair wire. Under the 10BASE-T standard, workstations are cabled using pairs of twisted-pair wire (one twisted-pair set being used for transmission and another twisted-pair set for reception) to Medium Access Units (MAUs). Each MAU normally has a built-in Attachment Interface Unit (AIU) that can be cabled to a coaxial transceiver connected to coaxial cable.
However, because home phone lines are traditionally considered to be a narrowband communications links permitting only a low data rate signal, bringing Ethernet to the home environment would ordinarily have required new wiring in virtually every home. It is therefore desirable to have a system that permits Ethernet-class data communications systems to be implemented in a home environment without requiring recabling.
Some proposed solutions to this home networking problem include the use of standard modem technology and digital subscriber line (xDSL) technology. One of the problems with standard modem technology is that it is currently limited to data speeds of 56 Kbps (by technology) (and to about 53 Kbps by FCC regulations) and further requires very complicated circuitry. Although XDSL technology can transmit data at a much higher rate that standard modem technology, potentially up to 4 Mbps, the cost of implementing this technology is very high and additionally it requires quite complicated modulation methods.
Yet another proposed solution to the home networking problem is a wireless solution. Wireless solutions are currently very expensive to implement and do not yet have the reliability of wired solutions.
One existing wireline home networking product is the HR1300T product of TUT Systems. The HR1300T system uses a “time modulation line code” to provide an in-home network over existing phone lines. However, this modulation scheme permits only a, relatively slow, 1.3 Mbps data rate.
Therefore, it will be appreciated by those of ordinary skill in the art that there is a need to provide a low-cost home networking solution that can provide high data rates and yet is both easy to install and use even while being compatible with the use of a single twisted pair wireline cable in a home environment.
SUMMARY OF THE INVENTION
In one aspect, the present invention overcomes the above-identified problems as well as other shortcomings and deficiencies of existing technologies by providing a system and method that enables seamless 10BASE-T Ethernet compatible data communications between computers and peripherals over standard single “twisted-pair” phone line that does not conflict or interfere with other signals, such as POTS or xDSL signals, that are being transmitted over the same phone line.
The present invention further provides a system and method for seamless 10BASE-T compatible data communications over an standard single “twisted-pair” home phone line between multiple computers, between computers and peripherals or between multiple peripherals. In one aspect of the present invention, each component that is to communicate over the home phone line has a 10BASE-T compatible Network Interface Card (NIC) for interfacing with the device.
The device of the present invention includes a Manchester coder, a pair of differential converters, a baseband processor, a modulator, a demodulator, filters, amplifiers, and a transmit/receive switch. A transmit/receive switch is used to switch the device between a transmit mode and a receive mode. When a signal is being transmitted from a component, the Manchester coder decodes signals received from the NIC. A differential converter is used to convert the differential signal received from the NIC to a unitary signal. A modulator is next used to modulate this unitary signal to a Radio Frequency (RF) signal using a selected modulation scheme, e.g., the Phase Shift Keying (PSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM) or Multicarrier Modulation (MCM) schemes.
A filter is used to limit the bandwidth of the modulated signal while a driver is used to amplify the signal to match the impedance of the phone line. When the device is receiving a signal from the phone line, the received signal is filtered with a bandpass filter and amplified using an amplifier. The signal is demodulated using an appropriate demodulation scheme. The demodulated signal is differentially encoded. The Manchester coder encodes the signal and sends it to the receiving NIC.


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