Apparatus for transmitting and/or receiving data at different data transfer rates especially in applications such as dual-rate ethernet local-area networks

Claim 2

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate, the first transmitter containing a digital waveshaper that at least partially provides the low-pass filtering in the first transmitter; and a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate.

Claim 3

Apparatus as in claim 1 further including a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter.

Claim 4

Apparatus as in claim 2 wherein the transformer is electronically coupled through the transmit filter to the connecting unit.

Claim 5

Apparatus as in claim 1 wherein: outgoing data at the first data rate has a first characteristic data rate frequency; and outgoing data at the second data rate has a second characteristic data rate frequency greater than the first characteristic data rate frequency.

Claim 6

Apparatus as in claim 4 wherein: the first transmitter has a low-pass cut-off frequency in the range extending between the characteristic data rate frequencies; and the apparatus includes a transmit filter that low-pass filters outgoing data from the second transmitter, the transmit filter having a low-pass cut-off frequency greater than or equal to the second characteristic data rate frequency.

Claim 7

Apparatus as in claim 1 further including a pair of first impedance elements, outgoing data from the first transmitter being transmitted differentially through the first impedance elements respectively to a pair of first electrical conductors coupled to the primary winding.

Claim 8

Apparatus as in claim 6 further including a pair of second impedance elements, outgoing data from the second transmitter being transmitted differentially on a pair of second electrical conductors coupled to the primary winding, each second impedance element coupled between a source of a common reference voltage and a corresponding one of the second electrical conductors.

Claim 9

Apparatus as in claim 7 wherein each impedance element comprises a resistor.

Claim 10

Apparatus as in claim 7 further including rate circuitry that determines whether outgoing data is to be transmitted at the first data rate or at the second data rate and generates a corresponding data rate signal.

Claim 11

Apparatus as in claim 9 further including a pair of switches respectively corresponding to the second impedance elements, each switch coupled in series with the corresponding second impedance element between the source of the common reference voltage and the corresponding second electrical conductor, the switches opening when the data rate signal indicates that outgoing data is to be transmitted at the first data rate and closing when the data rate signal indicates that outgoing data is to be transmitted at the second data rate.

Claim 12

Apparatus as in claim 1 further including a common-mode choke through which the secondary winding is electronically coupled to the connecting unit.

Claim 13

Apparatus as in claim 1 further including: a first transmit state machine that performs state functions on digital data to produce data supplied at the first data rate to the first transmitter; a second transmit state machine that performs state functions on digital data to produce data supplied at the second data rate to the second transmitter; and selection circuitry that selectively passes digital data either to the first state machine or to the second state machine.

Claim 14

Apparatus as in claim 1 further including: a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further primary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further primary winding; a first receiver that differentially receives incoming data from the further secondary winding largely at the first data rate; and a second receiver that differentially receives incoming data from the further secondary winding largely at the second data rate.

Claim 15

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; and a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation, incoming data from the secondary winding being provided differentially during normal apparatus operation on a pair of electrical conductors non-interruptibly coupled to both receivers and to the secondary winding.

Claim 16

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; and a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation, incoming data from the secondary winding being provided differentially during normal apparatus operation on a pair of electrical conductors non-interruptibly coupled to both receivers and to the secondary winding.

Claim 17

Apparatus as in claim 14 further including a terminating network at which the electrical conductors are terminated and through which incoming data from the secondary winding is supplied to a specified one of the receivers.

Claim 18

Apparatus as in claim 15 wherein the terminating network comprises: a pair of first impedance elements, each coupled between (a) a corresponding one of the electrical conductors and (b) a corresponding one of a pair of nodes coupled to the specified receiver; and a pair of second impedance elements, each coupled between (a) a corresponding one of the nodes and (b) a source of a common reference voltage so that the second impedance elements respectively form a pair of voltage dividers with the first impedance elements.

Claim 19

Apparatus as in claim 16 wherein each impedance element comprises a resistor.

Claim 20

Apparatus in claim 15 wherein the electrical conductors are capacitively coupled to the remaining one of the receivers.

Claim 21

Apparatus as in claim 18 wherein the specified and remaining receivers respectively are the second and first receivers.

Claim 22

Apparatus as in claim 14 further including at least one of a receive filter and a common-mode choke through which the secondary winding is non-interruptibly coupled to the pair of electrical conductors.

Claim 23

Apparatus as in claim 14 further including: a first receive state machine that performs state functions on data received from the first receiver at the first data rate to produce further data; a second receive state machine that performs state functions on data received from the second receiver at the second data rate to produce further data; and selection circuitry that selectively passes further data either from the first state machine or from the second state machine.

Claim 24

Apparatus as in claim 14 further including: a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further secondary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further secondary winding; a first transmitter that differentially transmits outgoing data to the further primary winding largely at the first data rate; and a second transmitter that differentially transmits outgoing data to the further primary winding largely at the second data rate.

Claim 25

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a connecting unit (a) electronically coupled to the secondary winding of the transmit transformer and connectable to a pair of lines of an outgoing twisted-pair cable so as to electronically couple the outgoing cable to the transmit transformer and (b) electronically coupled to the primary winding of the receive transformer and connectable to a pair of lines of an incoming twisted-pair cable so as to electronically couple the incoming cable to the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation.

Claim 26

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a connecting unit (a) electronically coupled to the secondary winding of the transmit transformer and connectable to a pair of lines of an outgoing twisted-pair cable so as to electronically couple the outgoing cable to the transmit transformer and (b) electronically coupled to the primary winding of the receive transformer and connectable to a pair of lines of an incoming twisted-pair cable so as to electronically couple the incoming cable to the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation.

Claim 27

Apparatus as in claim 23 wherein the second data rate is greater than the first data rate.

Claim 28

Apparatus as in claim 24 further including a transmit filter that low-pass filters outgoing data from the second transceiver at a frequency bandwidth greater than that of the first transceiver.

Claim 29

Apparatus as in claim 25 wherein the transmit transformer is electronically coupled through the transmit filter to the connecting unit.

Claim 30

Apparatus as in claim 24 further including: a pair of first impedance elements, output data from the first transceiver being transmitted differentially through the first impedance elements respectively to a pair of first electrical conductors coupled to the primary winding of the transmit transformer; and a pair of second impedance elements, output data from the second transceiver being transmitted differentially on a pair of second electrical conductors coupled to the primary winding of the transmit transformer, each second impedance element coupled between a source of a common reference voltage and a corresponding one of the second electrical conductors.

Claim 31

Apparatus as in claim 27 further including rate circuitry that determines whether outgoing or incoming data is to be transferred at the first data rate or at the second data rate and generates a corresponding data rate signal.

Claim 32

Apparatus as in claim 28 further including a pair of switches respectively corresponding to the second impedance elements, each switch coupled in series with the corresponding second impedance element between the source of the common reference voltage and the corresponding second electrical conductor, the switches opening when the data rate signal indicates that output data is to be transferred at the first data rate and closing when the data rate signal indicates that output data is to be transferred at the second data rate.

Claim 33

Apparatus as in claim 27 wherein incoming data from the secondary winding of the receive transformer is provided differentially during normal apparatus operation on a pair of third electrical conductors non-interruptibly coupled to both transceivers and to the secondary winding of the receive transformer.

Claim 34

Apparatus as in claim 23 further including: a first state machine coupled to the first transceiver; a second state machine coupled to the second transceiver; and a multiplexer coupled to the state machines.

Claim 35

Apparatus as in claim 23 further including an optical transceiver coupled to the twisted-pair cables and to at least one optical cable.

Claim 36

Apparatus as in claim 23 wherein the apparatus meets the standards of IEEE Specification 802.3.

Claim 37

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding substantially in accordance with the 10 Base-T protocol, the first transmitter containing a digital waveshaper that at least partially provides the low-pass filtering in the first transmitter; and a second transmitter that differentially transmits outgoing data to the primary winding substantially in accordance with the 100 Base-TX protocol.

Claim 38

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding substantially in accordance with the 10 Base-T protocol, the first transmitter containing a digital waveshaper that at least partially provides the low-pass filtering in the first transmitter; and a second transmitter that differentially transmits outgoing data to the primary winding substantially in accordance with the 100 Base-TX protocol.

Claim 39

Apparatus as in claim 34 further including a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter.

Claim 40

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding substantially in accordance with the 10 Base-T protocol; and a second receiver that differentially receives incoming data from the secondary winding substantially in accordance with the 100 Base-TX protocol, incoming data from the secondary winding being provided during normal apparatus operation along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation, incoming data from the secondary winding being provided differentially during normal apparatus operation on a pair of electrical conductors non-interruptibly coupled to both receivers and to the secondary winding.

Claim 41

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding substantially in accordance with the 10 Base-T protocol; and a second receiver that differentially receives incoming data from the secondary winding substantially in accordance with the 100 Base-TX protocol, incoming data from the secondary winding being provided during normal apparatus operation along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation, incoming data from the secondary winding being provided differentially during normal apparatus operation on a pair of electrical conductors non-interruptibly coupled to both receivers and to the secondary winding.

Claim 42

Apparatus as in claim 36 further including a terminating network at which the electrical conductors are terminated and through which incoming data from the secondary winding is supplied to a specified one of the receivers.

Claim 43

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a connecting unit (a) electronically coupled to the secondary winding at the transmit transformer and connectable to a pair of lines of an outgoing twisted-pair cable so as to electronically couple the outgoing cable to the transmit transformer and (b) electronically coupled to the primary winding of the receive transformer and connectable to a pair of lines of an incoming twisted-pair cable so as to electronically couple the incoming cable to the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer substantially in accordance with the 10 Base-T protocol and (b) differentially receives incoming data from the secondary winding of the receive transformer substantially in accordance with the 10 Base-T protocol; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer substantially in accordance with the 100 Base-TX protocol and (b) differentially receives incoming data from the secondary winding of the receive transformer substantially in accordance with the 100 Base-TX protocols, incoming data from the secondary winding of the receiving transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data.

Claim 44

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a connecting unit (a) electronically coupled to the secondary winding at the transmit transformer and connectable to a pair of lines of an outgoing twisted-pair cable so as to electronically couple the outgoing cable to the transmit transformer and (b) electronically coupled to the primary winding of the receive transformer and connectable to a pair of lines of an incoming twisted-pair cable so as to electronically couple the incoming cable to the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer substantially in accordance with the 10 Base-T protocol and (b) differentially receives incoming data from the secondary winding of the receive transformer substantially in accordance with the 10 Base-T protocol; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer substantially in accordance with the 100 Base-TX protocol and (b) differentially receives incoming data from the secondary winding of the receive transformer substantially in accordance with the 100 Base-TX protocols, incoming data from the secondary winding of the receiving transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data.

Claim 45

Apparatus as in claim 38 further including a transmit filter that low-pass filters outgoing data from the second transceiver at a frequency bandwidth greater than that of the first transceiver.

Claim 46

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; and an optical transceiver connectable to at least one optical cable and electronically coupled to (a) the secondary winding of the transmit transformer and (b) the primary winding of the receive transformer.

Claim 47

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; and an optical transceiver connectable to at least one optical cable and electronically coupled to (a) the secondary winding of the transmit transformer and (b) the primary winding of the receive transformer.

Claim 48

Apparatus as in claim 40 wherein the second data rate is greater than the first data rate.

Claim 49

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; means for (a) providing outgoing data from the secondary winding of the transmit transformer to cable means and (b) for providing incoming data from the cable means to the primary winding of the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation.

Claim 50

Electronic apparatus comprising: a transmit isolation transformer having a primary winding and a secondary winding; a receive isolation transformer having a primary winding and a secondary winding; means for (a) providing outgoing data from the secondary winding of the transmit transformer to cable means and (b) for providing incoming data from the cable means to the primary winding of the receive transformer; a first transceiver that (a) low-pass filters digital data to produce outgoing data which the first transceiver differentially transmits to the primary winding of the transmit transformer largely at a first data transfer rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the first data rate; and a second transceiver that (a) differentially transmits outgoing data to the primary winding of the transmit transformer largely at a second data transfer rate different from the first data rate and (b) differentially receives incoming data from the secondary winding of the receive transformer largely at the second data rate, incoming data from the secondary winding of the receive transformer being provided along data transfer paths that extend from the secondary winding of the receive transformer through where one of the transceivers physically receives incoming data to where the other of the transceivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation.

Claim 51

Apparatus as in claim 42 wherein the second data rate is greater than the first data rate.

Claim 52

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate grater than the first data rate; and a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter, the transformer being electronically coupled through the transmit filter to the connecting unit.

Claim 53

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate grater than the first data rate; and a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter, the transformer being electronically coupled through the transmit filter to the connecting unit.

Claim 54

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; and a transmit filter that low-pass filters outgoing data from the second transmitter, where (a) outgoing data at the first data rate has a first characteristic data rate frequency, (b) outgoing data at the second data rate has a second characteristic data rate frequency greater than the first characteristic data rate frequency, (c) the first transmitter has a low-pass cut-off frequency in the range extending between the first and second characteristic data rate frequencies, and (d) the transmit filter has a low-pass cut-off frequency greater than or equal to the second characteristic data rate frequency.

Claim 55

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; and a transmit filter that low-pass filters outgoing data from the second transmitter, where (a) outgoing data at the first data rate has a first characteristic data rate frequency, (b) outgoing data at the second data rate has a second characteristic data rate frequency greater than the first characteristic data rate frequency, (c) the first transmitter has a low-pass cut-off frequency in the range extending between the first and second characteristic data rate frequencies, and (d) the transmit filter has a low-pass cut-off frequency greater than or equal to the second characteristic data rate frequency.

Claim 56

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a pair of first impedance elements, outgoing data from the first transmitter being transmitted differentially through the first impedance elements respectively to a pair of first electrical conductors coupled to the primary winding; and a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate.

Claim 57

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a pair of first impedance elements, outgoing data from the first transmitter being transmitted differentially through the first impedance elements respectively to a pair of first electrical conductors coupled to the primary winding; and a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate.

Claim 58

Apparatus as in claim 46 further including a pair of second impedance elements, outgoing data from the second transmitter being transmitted differentially on a pair of second electrical conductors coupled to the primary winding, each second impedance element coupled between a source of a common reference voltage and a corresponding one of the second electrical conductors.

Claim 59

Apparatus as in claim 47 wherein each impedance element comprises a resistor.

Claim 60

Apparatus as in claim 48 further including rate circuitry that determines whether outgoing data is to be transmitted at the first data rate or at the second data rate and generates a corresponding data rate signal.

Claim 61

Apparatus as in claim 49 further including a pair of switches respectively corresponding to the second impedance elements, each switch coupled in series with the corresponding second impedance element between the source of the common reference voltage and the corresponding second electrical conductor, the switches opening when the data rate signal indicates that outgoing data is to be transmitted at the first data rate and closing when the data rate signal indicates that outgoing data is to be transmitted at the second data rate.

Claim 62

Apparatus as in claim 46 further including a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter.

Claim 63

Apparatus as in claim 51 wherein the transformer is electronically coupled through the transmit filter to the connecting unit.

Claim 64

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a common-mode choke through which the secondary winding is electronically coupled to the connecting unit; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; and a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate.

Claim 65

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a common-mode choke through which the secondary winding is electronically coupled to the connecting unit; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; and a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate.

Claim 66

Apparatus as in claim 53 further including a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter.

Claim 67

Apparatus as in claim 54 wherein the transformer is electronically coupled through the transmit filter to the connecting unit.

Claim 68

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; a first transmit state machine that performs state functions on digital data to produce data supplied at the first data rate to the first transmitter; a second transmit state machine that performs state functions on digital data to produce data supplied at the second data rate to the second transmitter; and selection circuitry that selectively passes digital data either to the first state machine or to the second state machine.

Claim 69

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; a first transmit state machine that performs state functions on digital data to produce data supplied at the first data rate to the first transmitter; a second transmit state machine that performs state functions on digital data to produce data supplied at the second data rate to the second transmitter; and selection circuitry that selectively passes digital data either to the first state machine or to the second state machine.

Claim 70

Apparatus as in claim 56 further including a transmit filter that low-pass filters outgoing data from the second transmitter at a frequency bandwidth greater than that of the first transmitter.

Claim 71

Apparatus as in claim 57 wherein the transformer is electronically coupled through the transmit filter to the connecting unit.

Claim 72

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further primary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further primary winding; a first receiver that differentially receives incoming data from the further secondary winding largely at the first data rate; and a second receiver that differentially receives incoming data from the further secondary winding largely at the second data rate.

Claim 73

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the secondary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the secondary winding; a first transmitter that low-pass filters digital data to produce outgoing data which the first transmitter differentially transmits to the primary winding largely at a first data transfer rate; a second transmitter that differentially transmits outgoing data to the primary winding largely at a second data transfer rate greater than the first data rate; a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further primary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further primary winding; a first receiver that differentially receives incoming data from the further secondary winding largely at the first data rate; and a second receiver that differentially receives incoming data from the further secondary winding largely at the second data rate.

Claim 74

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; a first receive state machine that performs state functions on data received from the first receiver at the first data rate to produce further data; a second receive state machine that performs state functions on data received from the second receiver at the second data rate to produce further data; and selection circuitry that selectively passes further data either from the first state machine or from the second state machine.

Claim 75

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; a first receive state machine that performs state functions on data received from the first receiver at the first data rate to produce further data; a second receive state machine that performs state functions on data received from the second receiver at the second data rate to produce further data; and selection circuitry that selectively passes further data either from the first state machine or from the second state machine.

Claim 76

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further secondary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further secondary winding; a first transmitter that differentially transmits outgoing data to the further primary winding largely at the first data rate; and a second transmitter that differentially transmits outgoing data to the further primary winding largely at the second data rate.

Claim 77

Electronic apparatus comprising: an isolation transformer having a primary winding and a secondary winding; a connecting unit electronically coupled to the primary winding and connectable to a pair of lines of a twisted-pair cable so as to electronically couple the twisted-pair cable to the primary winding; a first receiver that differentially receives incoming data from the secondary winding largely at a first data transfer rate; a second receiver that differentially receives incoming data from the secondary winding largely at a second data transfer rate greater than the first data rate, incoming data from the secondary winding being provided along data transfer paths that extend from the secondary winding through where one of the receivers physically receives incoming data to where the other of the receivers physically receives incoming data, the data transfer paths having a characteristic impedance that is largely constant during normal apparatus operation; a further isolation transformer having a further primary winding and a further secondary winding, the connecting unit being electronically coupled to the further secondary winding and connectable to a pair of lines of a further twisted-pair cable so as to electronically couple the further twisted-pair cable to the further secondary winding; a first transmitter that differentially transmits outgoing data to the further primary winding largely at the first data rate; and a second transmitter that differentially transmits outgoing data to the further primary winding largely at the second data rate.