US 5,517,487 A · System for increasing the capacity of existing local area networks that use shielded twisted wire pair medium

Abstract

The data communication capacity of an existing local area network (LAN) 10 that uses a shielded twisted wire pair 16 as its transmission medium may be increased with the addition of special frequency selective terminators 36 and single-ended transceivers 20. The single-ended transceivers 20 have two single-ended transmitter connections 42,44 to the two twisted wires 22,24 in the shielded twisted wire pair medium 16, respectively, and one single-ended receiver connection 46 to one of the two twisted wires 22,24 in the shielded twisted wire pair medium 16. The shielded twisted wire pair medium 16 is terminated by the special frequency selective terminators 36 which provide transmission line impedance matching over the signal bandwidth of a single-ended data channel, while providing a high impedance over the signal bandwidth of a differential data channel. Thus, differential data communications are allowed over the signal bandwidth of the differential data channel, while single-ended data communications are allowed over the signal bandwidth of the single-ended data channel, thereby increasing the overall data communication capacity of the LAN.

Claims16

Dependent claims

A system for increasing the data communication capacity of an existing local area network (LAN) that uses a shielded twisted wire pair medium having two conductors and a shield for shielding said two conductors, each said conductor and shield having two ends, said two conductors forming a primary transmission line having a first characteristic impedance for transmission of signals within a first signal bandwidth, the shielded twisted pair medium thereby supporting differential data communications at a first frequency within the first signal bandwidth, said system comprising:

a secondary transmission line formed by each of said two conductors and said shield, said secondary transmission line having a second characteristic impedance for transmission of signals within a second signal bandwidth;
first terminating means for terminating said primary transmission line at both ends with an impedance matching said first characteristic impedance;
second terminating means for selectively terminating said secondary transmission line at both ends with a high impedance over the first signal bandwidth and with an impedance matching said second characteristic impedance over the second signal bandwidth;
a plurality of primary transceivers differentially connected to said primary transmission line for providing differential data communications over said primary transmission line at a frequency within said first signal bandwidth;
and
a plurality of secondary transceivers single-endedly connected to said secondary transmission line for providing single-ended data communications over said secondary transmission line at a frequency within said second signal bandwidth.

3 more elements

A method for increasing the data communication capacity of an existing local area network (LAN) that uses a shielded twisted wire pair medium having two conductors and a shield for shielding said two conductors, each said conductor and shield having two ends, said two conductors forming a primary transmission line having a first characteristic impedance for transmission of signals within a first signal bandwidth, the shielded twisted pair medium thereby supporting differential data communications at a first frequency within the first signal bandwidth, said method comprising the steps of:

forming a secondary transmission line from said two conductors and said shield in said transmission medium, said secondary transmission line having a second characteristic impedance for transmission of signals within a second signal bandwidth;
terminating said primary transmission line at both ends with a first terminating means that matches said first characteristic impedance;
selectively terminating said secondary transmission line at both ends with a second terminating means that provides a high impedance over the first signal bandwidth and an impedance matching said second characteristic impedance over the second signal bandwidth;
differentially connecting a plurality of primary transceivers to said primary transmission line for providing differential data communications over said primary transmission line at a frequency within said first signal bandwidth;
and
single-endedly connecting a plurality of secondary transceivers to said secondary transmission line for providing single-ended data communications over said secondary transmission line at a frequency within said second signal bandwidth.

3 more elements

Dependencies are inferred from the claim text.

System for increasing the capacity of existing local area networks that use shielded twisted wire pair medium

Life of this patent

System for increasing the capacity of existing local area networks that use shielded twisted wire pair medium

Life of this patent

Abstract

Claims16