Background of the Invention Internetworking of computer systems is well-known in the art. There are various networking standards, such as Ethernet, Token Ring, and IP which allow personal computers to communicate between themselves, either within one facility (local area networking), or over the entire globe (wide area networking). Such networks are widely used to share computer resources, such as file storage, and peripherals, such as printers. Most existing computer networks are used to communicate nondeterministic-bandwidth data, i.e. data which is not affected by its transfer rate or transfer delays.

With the increasing use of computers for processing multimedia data types, networking standards are evolving for the simultaneous communication of nondeterministic-bandwidth data and deterministic-bandwidth data, i.e. data which is communicated at some well-defined rate with some maximum tolerance for transfer delays. An example of this is the use of isochronous Ethernet to communicate deterrninistic-bandwidth data, such as voice or compressed video, along with nondeterministic-bandwidth data.

Relatively small networks of computers are appearing, which are connected to each other using networking standards capable of multi-megabit transmission rates, and which are connected to a wide area network using analog modems or ISDN (Integrated Services Digital Network) modems. One practical problem with implementing small networks on a wide scale basis is that current networking standards, both local area and wide area, require new premises wiring.

Conventional telephone wiring, usually a common single-pair wire that runs in the walls of a home or small office, does not support existing networking standards because: many of those standards require terminated wiring and existing common single-pair wiring may have unterminated "stub" runs; standards may require a defined network topology which is not necessarily present in

existing telephone wiring; and standards may not allow electrically commoned end-user devices, such as telephones on common single-pair wiring. Installation of media or network topologies more appropriate for currently existing standards such as Ethernet or ISDN encounters consumer resistance because such changes to preexisting wiring is both expensive and disruptive.

Summary of the Invention A method, apparatus and system is provided which allows end-user devices to be internetworked over common single-pair wiring in such a way that multi-megabit transmission rates of both nondeterministic bandwidth data and deterministic bandwidth data is supported.

Nondeterministic bandwidth data and deterministic bandwidth data are simultaneously communicated between devices.

A number of end-user devices, e.g. telephones, computers, or other information processing devices, are networked together by digitally coupling each of the devices to at least another one of the devices. Devices are generally coupled to one another using a common single- pair wire. Using this common single-pair wire, devices exchange deterministic-bandwidth data and nondeterministic-bandwidth data with other devices on the network. In some embodiments, one of the devices is a control unit which synchronizes the communication of deterministic- bandwidth data between devices. Nondeterministic-bandwidth data is communicated directly from an originating device to a destination device, without being first passed through the master control unit. In certain embodiments, the control unit is also coupled to an external power network and an external telephone network.

In some embodiments, the devices are coupled at irregular intervals along the common single-pair wire. In still other embodiments, certain ones of the devices are connected by media other than common single-pair wire, e.g. coaxial cable. In these mixed media embodiments, nondeterministic-bandwidth data is communicated from one device to a second device, regardless of the medium by which the devices are connected.

In another aspect, the invention is a method for coupling a plurality of end-user devices together, such that simultaneous multi-megabit transmission of nondeterministic-bandwidth data and deterministic-bandwidth data over common single-pair wiring is supported. Device adapters are provided, which are associated with an end-user device, and digitally coupled to at least

another one of the device adapters via a common single-pair wire. Deterministic-bandwidth data and nondeterministic-bandwidth data is simultaneously communicated between the adapters over the common single-pair wire.

In some embodiments, the adapters are coupled at irregular intervals along the common single-pair wire. In still other embodiments, some of the adapters are connected by media other than common single-pair wire, e.g. coaxial cable. In these mixed-media embodiments, nondeterministic-bandwidth data is communicated from one device to a second device, regardless of the medium by which the devices are connected. In certain embodiments, the control unit is also coupled to an external power network and an external telephone network.

In another aspect, the invention is a system for simultaneously communicating deterministic-bandwidth data and nondeterministic-bandwidth data over a common single-pair wire. In this system, at least two end-user devices are digitally coupled to a common single-pair wire and a control unit is digitally coupled to the common single-pair wire. In some embodiments, the control unit is also coupled to an external telephone network and an external power network. The control unit synchronizes communication of deterministic-bandwidth data between devices coupled to the single-pair wire. Nondeterministic-bandwidth data is communicated directly from one device to a second device. In some embodiments, each of the devices are digitally coupled to the common single-pair wire by a device adapter. In some other embodiments, some of the devices are connected by media other than common single-pair wire.

In yet another aspect, the invention is an adapter for coupling end-user devices to a common single-pair wire such that the device may simultaneously communicate deterministic- bandwidth and nondeterministic-bandwidth data over the common single-pair wire. The adapter includes an end-user device connector for coupling the adapter to an associated end-user device, an network connector for coupling the adapter to the common single-pair wire, and interface circuitry which causes the adapter to communication deterministic-bandwidth and nondeterministic-bandwidth data over the common single-pair wire. In some embodiments, the adapter also includes a power connector for connecting to an external power source. The adapter may be built into its associated end-user device or it may be provided as an external mechanism.

In some embodiments, the adapter includes a network connector which connects the adapter to a network other than a common single-pair wire network.

Brief Description of the Drawings This invention is pointed out with particularity in the appended claims. The above and further advantages of this invention may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a block diagram of an embodiment of the system; FIG. 2 is a block diagram of an embodiment of the invention showing unterminated spurs; FIG. 3 is a functional block diagram of one embodiment of an adapter for use with a telephone; FIG. 4 is a functional block diagram of one embodiment of an adapter for use with a personal computer; and FIG. 5 is a functional block diagram of one embodiment of a master control unit.

Detailed Description of the Invention Referring now to FIG. 1, a system for interconnecting a number of end-user devices 12 is shown. End-user device 12 may be any electrical, mechanical, or electromechanical device which has the capability of communicating data to, or receiving data from, some other device, such as a television, personal computer, facsimile machine, laser printer, or telephone. The end-user device 12 connects to the network via an adapter 14. The adapter 14 may be external to the end-user device 12 or it may be built into the device 12'. Although one adapter 14 is shown for each end- user device 12 in FIG. 1, each end-user device 12 may be provided with one or more adapters 14 for connection to other devices 12 or other networks.

For embodiments in which the adapter 14 is provided as a separate unit from the end-user device 12, the adapter 14 communicates with the end-user device 12 through any one of a number of connection mechanisms including, but not limited to, direct electrical connection or wireless communication. In general, each adapter 14 is connected to the rest of the system by a common single-pair wire. As used in this application, the term "common single-pair wire" refers to a single-pair of wires to which each device is electrically connected, such as the type of wire generally used to provide telephone access in a house. This is in contrast to thick Ethernet, which runs over a coaxial cable that is not electrically common to all of the attached devices and 10 Base-T (category 3) cable, which uses two pairs of wires, one for sending data and one for receiving data.

The techniques of the present application are not limited to networks consisting solely of common single-pair wiring, however; hybrid networks can be formed by interconnecting a traditional computer network, e.g. coaxial cable network or category 3 cable network, with the common single-pair wire network using a bridging adapter (not shown), which provides network connections for the different types of networks to be bridged.

The devices 12 may be connected together using any topology. For example, if the network is installed before the devices 12 are provided, or simultaneously with their provision, then a topology may be selected because of its ease of installation, such as a ring topology.

However, if the single-pair wire is pre-existing, e.g. telephone wire in a house, then the devices 12 may be connected together using the currently existing topology, which may have various network abnormalities, such as the unterminated stubs 15 shown in FIG. 2.

The data transferred between end-user devices 12 may be distinguished into two classes: deterministic-bandwidth data and nondeterministic-bandwidth data. Deterministic-bandwidth data is data which is communicated at some well-defined rate with some maximum tolerance for transfer delays. For example, digitally encoded voice using a 64 kbits/s PCM encoding requires a data channel of exactly 64 kbits/s. In the event 64 kbits/s of deterministic-bandwidth is not available there is no graceful degradation. This is in contrast to nondeterministic-bandwidth data, such as file transfers between computers. File transfers take place using as much bandwidth as is available, and the only degradation resulting from less bandwidth is that the transfer takes more time.

In the present system, deterministic-bandwidth data is switched between two or more adapters 14. An originating adapter 14 transmits deterministic-bandwidth data either to the control unit 11 or to a destination adapter 14. The control unit 11 synchronizes the transfer of deterministic-bandwidth data. Generally, however, the control unit 11 provides functionality in addition to, or in lieu of, adapter functionality, such as a connection to resources outside the network of devices 12. The control unit 11, which is discussed in more detail below, can transmit deterministic-bandwidth data received from the originating adapter 14 to the destination adapter 14. Thus, the control unit 11 allows audio packets to be switched between adapters 14 in order to produce a Private Branch Exchange (PBX) system.

In general, data may be transmitted using any protocol. In one embodiment, data transfers occur in fixed time periods called "frames." Each frame begins with a variable number of fixed slots which provide for the transmission of deterministic-bandwidth data. The remainder of the data frame, i.e. the portion of the data frame left over after all fixed slots have occurred, is available for nondeterministic data transfers. Each frame is generally less than one second in duration. Thus, while data transfers are not truly simultaneous, deterministic-bandwidth data transferred during a fixed slot and nondeterministic-bandwidth data transferred during the remainder of the data appear to occur simultaneously. Thus, for the purposes of this application, it is said that the data is "simultaneously" communicated.

For example, an adapter 14 which desires to initiate a deterministic data transfer, such as an adapter associated with a telephone which has been lifted from its hook, requests that the control unit 11 assign a fixed slot to it. The control unit 11 will assign a fixed slot to the adapter 14 provided that there is a fixed slot available. The system may have a predetermined limit on the number of fixed slots that ensures some of the data frame remains for nondeterministic-bandwidth data transfers, or the system may allow the entire data frame to be assigned as fixed slots. In the latter case, the control unit 11 assigns a fixed slot to the adapter 14 so long as there is a slot available in the data frame.

Once the control unit 11 has assigned a fixed slot to the adapter 14, deterministic- bandwidth data is communicated between the adapter 14 and the control unit 11 during this slot of each data frame. Adapters 14 wishing to transmit nondeterministic data, e.g. adapters connected to personal computers that have file transfers to accomplish, arbitrate for control of the remaining portion of the data frame using any arbitration scheme, such as carrier sense with collision detect. Once an adapter 14 has control of the network, it may begin its nondeterrninistic- bandwidth data transfer.

The control unit 11 generally includes a microcontroller, which permits the control unit 11 to fulfill its functions in connection with the network, i.e. assigning fixed slots to adapters 14 and communicating with adapters 14 during those fixed slots. In addition to providing these functions, the control unit 11 may connect the network with resources outside the immediate network of devices 12, for example, the control unit 11 may provide electrical connection to

outside telephone lines, outside power lines, and coaxial cables used by, among others, cable television providers.

For example, an outside telephone line can be connected to a conventional switched network interface. The switched network interface may be connected to one or more devices which provide various conventional functions, such as modem functions, facsimile functions, caller identification, and call progress functions. In addition, the control unit 11 generally includes a power supply which interfaces to an outside network of power lines and provides power to the network and the control unit 11 itself.

FIG. 3 depicts the functional block diagram of one embodiment of an adapter 20 for use with a telephone. The telephone adapter 20 has network connector 22 and a telephone connector 34. The network connector 22 allows the telephone adapter 20 to communicate with other adapters 14 connected to the network. The network connector 22 may be implemented with any appropriate connector such as an lull connector. The telephone connector 34 provides a traditional connection to the telephone device 12 associated with the adapter 14, e.g. an RJ11 connector, as well as a power and audio interface to the device 12.

The handset driver 32 provides DC power to the telephone device 12 associated with the adapter 14. The handset driver 32 also provides proper impedance matching in the audio band for incoming and outgoing audio signals.

The signal converter 30 converts analog audio signals received from the end-user device 12 into a fixed-bandwidth, digital representation of those signals. The converter 30 also generates audio signals from digital signals received via the network. Any appropriate digital encoding for an analog signal can be used, such as PCM (pulse code modulation).

The microcontroller 28 creates packets of digital information appropriate for transmission over the network from the fixed-bandwidth digital signal created by the signal converter 30. The microcontroller 28 also assembles packets received from the network into a digital signal that may be converted to audio by the converter 30.

The network transceiver 26 drives signals onto the network when the telephone adapter 20 is transmitting and conditions signals received from the network when the telephone adapter

20 is receiving. Signal condition may include boosting the gain of received signals, filtering stray voltage from the audio signal, or other known signal-conditioning techniques.

The power supply 24 conditions DC power, which is distributed over the common single- pair wire. The DC power is separated from the network signals and regulated to power the telephone adapter 20 circuitry.

FIG. 4 depicts the functional block diagram of one embodiment of an adapter 40 for use with a computer. The computer adapter 40 has a network connector 42, a computer interface connector 54 and a power connector 44. The network connector 42 allows the computer adapter 40 to communicate with other adapters 14 connected to the network. The network connector 42 may be implemented with any appropriate connector. The computer interface connector 54 provides a connection to the computer using some standard interface. This could be a serial port interface, parallel port interface, Ethernet interface, a computer bus interface or some combination of these or other standard interfaces. The power connector 44 provides power to the computer adapter 40 using some standard means, such as a wall transformer.

The computer interface circuitry 52 provides an interface between the computer interface signals and the microcontroller 50. The interface includes circuitry which handles both wide-area and local-area communications.

The microcontroller 50 converts deterministic-bandwidth computer data and nondeterministic-bandwidth computer data into packets of digital information appropriate for transmission over the network. The microcontroller 50 also converts packets of information received from the method into deterministic bandwidth and nondeterministic bandwidth computer data.

The network transceiver 48 drives signals onto the network when the computer adapter 40 is transmitting and conditions signals received from the network when the computer adapter 40 is receiving. The power supply 46 regulates incoming power to the computer adapter 40 circuitry.

Fig. 5 depicts the functional block diagram of one embodiment of a control unit 60. The control unit 60 has network connector 62, a gateway interface connector(s) 74 and a power

connector 64. The network connector 62 allows the control unit 60 to communicate with other adapters 14 connected to the network. The network connector 62 may be implemented with any appropriate physical connector. The gateway interface connector(s) 74 provides a connection to external local-area or wide-area network(s). This could be a modem interface, ISDN interface, Ethernet interface, telephone network interface, cable network interface, or some combination of these or other standard interfaces. The power connector 64 couples the control unit 60 to an external power source.

The gateway interface circuitry 72 provides an interface between the gateway interface signals and the microcontroller 70. This interface performs the functions necessary for exchanging data with the wide area or local area network(s) beyond the gateway interface connector(s) 74.

The microcontroller 70 interfaces the gateway data to the network side. The microcontroller 70 will generally convert the deterministic-bandwidth gateway data and nondeterministic-bandwidth gateway data to packets appropriate for transmission over the network, and perform the reverse function on incoming packets. The control unit also transmits synchronization packets over the network to coordinate communication between the various network adapters 14.

The network transceiver 68 drives signals onto the network when the control unit 60 is transmitting and conditions signals received from the network when the control unit 60 is receiving.

The power supply 66 regulates incoming power to the control unit 60 circuitry, and can couple the control unit 60 to an external power source in order to provide power for the control unit 60 and the network.

Having described preferred embodiments of the invention, it will now become apparent to one of skill in the art that other embodiments incorporating the concepts may be used. It is felt, therefore, that these embodiments should not be limited to disclosed embodiments but rather should be limited only by the spirit and scope of the following claims.