Electrical transmission or interconnection systems – Switching systems – Plural switches
Reexamination Certificate
1998-06-30
2001-08-28
Gaffin, Jeffrey (Department: 2836)
Electrical transmission or interconnection systems
Switching systems
Plural switches
Reexamination Certificate
active
06281605
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to networking of electronic devices and more particularly to a passive switching hub for networking multiple devices to a transmission medium.
2. Description of the Related Arts
A local area network is a communication system that allows personal computers, workstations, servers, and other network devices within a small area, such as a single building or a group of adjacent buildings, to transfer information between each other. Each device connected to the network communicates with other device on the network by following a standard which defines the operation of the network. One of the most widely accepted standards for local area networks is the IEEE 802.3 CSMA/CD Ethernet Protocol.
In the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) Ethernet Protocol, before transmitting data onto the network, each device first monitors the network to insure that no transmissions are currently in progress (Carrier Sense). When the network is idle (no transmissions in progress), each device can transmit information onto the network (Multiple Access). When more than one device transmits at the same time, each transmitting device must be able to detect this condition (Collision Detection), stop its transmission and retry.
The IEEE 802.3 CSMA/CD Ethernet protocol defines for physical layer specifications which differ primarily in the physical cables utilized. Coaxial cables are defined by a Thick Coax Ethernet (10BASE5), which utilizes a double-shielded coaxial cable, and a Thin Coax Ethernet (10BASE2), which utilizes a single-shielded coaxial cable. Twisted pair cables are 26 to 22 AWG unshielded wire. Two kinds of twisted pair exist. UTP is for unshielded, twisted pair, while STP is for shielded, twisted pair. UTP is what phone companies typically installed (though this is often not of high enough quality to support high-speed network use such as 10BaseT ethernet. UTP is graded according to its data carrying ability (e.g., Level 3, Level 4, Level 5). 10BaseT Ethernet requires at least Level 3 cable. Often what is now readily available is the Level 5 UTP having a RJ-45 connector.
Today, local area networks are becoming more and more prevalent and are often encountered to some degree by even casual computer users. Not only do personal computers, workstations, and servers utilize local area networks such as ethernet, but peripheral devices like printers, scanners, and digital cameras are also incorporating an ethernet interface. Ethernet being a relatively speedy and the widely accepted interface is becoming more popular in more devices. Thus, there is a growing need for providing readily available ethernet ports for new and existing devices, particularly for the causal computer users.
Even though multiple port hubs for ethernet having four ports, eight ports, 12 ports and even 24 ports are available, these hubs are often costly especially to cost conscience causal computer users. Moreover, even the smallest, a four port hub, takes up desk space and requires a separate power lead to an AC source. More often than not what is needed is an additional ethernet port than what is available.
For example, modern day network equipped computers have one network port and often that one network port is coupled to another network port fixed in of the wall for access to a local area network. Configured in this way leaves zero ports available for additional devices. The current available solutions for interfacing to another network equipped device are to 1) disconnect the current computer from the network and connect the other network device which may require crawling on hand and knees or 2) acquire a multiple port hub like the four port hub.
Even a stand alone user with only one network port on the back of the computer have needs for additional ports. If there is a printer connected to the network port and the user wants to connect a digital camera or scanner to the computer, the user will be unable without disconnecting and reconnecting already networked devices or purchasing at minimum a four port hub.
Therefore, it is desirable to provide a passive ethernet hub apparatus and methods of operating the same which provides a simpler less costly and cumbersome solution that better suits the network needs of its users.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for a multiport differential signal switcher and methods for operating the same which splits a transmission signal to provide multiple transmission signals. The multiport differential signal switcher is based on a plurality of switches for splitting the transmission signal. Thus, according to one aspect of the invention, the multiport differential signal switcher for operating on a signal originating from a signal source comprises a first port having a first transmit port and a first receive port configured to receive a signal at the first transmit port coupled to a first switching element and a second switching element, a second port having a second transmit port and a second receive port configured to receive a signal at the second receive port coupled to the second switching element and a third switching element, and a third port having a third transmit port and a third receive port configured to receive a signal at the third receive port coupled to the first switching element and a fourth switching element wherein the originating signal from the first transmit port turns-on the first switching element and the second switching element to pass the originating signal to the second receive port and the third receive port, respectively.
According to another aspect of the invention, the first switching element, the second switching element, the third switching element, and the fourth switching element each include a current switch. The first switching element includes a first resistor and a first npn transistor, a first end of the first resistor coupled to the first transmit port and a collector of the first npn transistor, a second end of the resistor coupled to a base of the first npn transistor, and an emitter of the first npn transistor coupled to the third receive port and an output of the fourth switching element, and the second switching element includes a second resistor and a second npn transistor, a first end of the second resistor coupled to the first transmit port and a collector of the second npn transistor, a second end of the second resistor coupled to a base of the second npn transistor, and an emitter of the second npn transistor coupled to the second receive port and an output of the third switching element. The first npn transistor of the first switching element and the second npn transistor of the second switching element are in an on-state.
According to another aspect of the invention, the third switching element includes a third resistor and a third npn transistor, a first end of the first resistor coupled to the second receive port and a collector of the third npn transistor, a second end of the resistor coupled to a base of the third npn transistor, and an emitter of the third npn transistor coupled to a third transmit port and an input of a fifth switching element, and the fourth switching element includes a fourth resistor and a fourth npn transistor, a first end of the fourth resistor coupled to the third receive port and a collector of the fourth npn transistor, a second end of the fourth resistor coupled to a base of the fourth npn transistor, and an emitter of the fourth npn transistor coupled to a second transmit port and an input of a sixth switching element. The third npn transistor of the third switching element and the fourth npn transistor of the fourth switching element are in an off-state. The first switching element, the second switching element, the third switching element, and the fourth switching element each include an unidirectional current switch.
An apparatus and method of operating a multiport differential signal switcher are provided whereby no external power supply is needed to sup
Gaffin Jeffrey
Hopen Daniel
Peninsula Law Group
Roberto Rios
Shinji Kichise
LandOfFree
Method and apparatus for passive switching hub does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for passive switching hub, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for passive switching hub will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2524402