Communication system and method over local area network wiring
View Patent ↗A device for enabling a local area network wiring structure to simultaneously carry digital data and analog telephone signals on the same transmission medium. It is particularly applicable to a network in star topology, in which remote data units (e.g. personal computers) are each connected to a hub through a cable comprising at least two pairs of conductors, providing a data communication path in each direction. Modules at each end of the cable provide a phantom path for telephony (voice band), signals between a telephone near the data set and a PBX, through both conductor pairs in a phantom circuit arrangement. All such communication paths function simultaneously and without mutual interference. The modules comprise simple and inexpensive passive circuit components.
1. A device for a local area network (LAN), the LAN including a LAN cable having at least four wire pairs to carry a plurality of data signals, and the device comprising:
a first transformer having a primary winding and a secondary winding, the first transformer being operative to pass a first data signal;
a second transformer having a primary winding and a secondary winding, the second transformer being operative to pass a second data signal;
a third transformer having a primary winding and a secondary winding, the third transformer being operative to pass a third data signal;
a fourth transformer having a primary winding and a secondary winding, the fourth transformer being operative to pass a fourth data signal, and the primary winding of each one of the transformers being communicatively coupled to a respective one of the four wire pairs, the secondary winding of each one of the transformers being arranged within the device for transferring a respective one of the data signals to or from the associated primary winding, and a first center-tap connection of the primary winding of any one of the transformers to be paired with a second center-tap connection of the primary winding of any other one of the transformers for providing a first phantom channel using the two respectively associated pairs of the four wire pairs;
circuitry configured to source a phantom signal over the phantom channel, the circuitry coupled to the first center-tap connection and the second center-tap connection; and
a single enclosure housing the circuitry and also housing the first, second, third and fourth transformers.
2. The device as claimed in claim 1 wherein the LAN and data communications within the LAN are based on the IEEE802.3 Ethernet standard.
3. The device as claimed in claim 2 further comprising at least 1000 Mb/s interfaces for communicative coupling to the at least four wire.
4. The device as claimed in claim 2 wherein the device is a multi-port data communication device.
5. The device as claimed in claim 4 wherein the multi-port data communication device is a switch.
6. The device as claimed in claim 4 wherein the multi-port data communication device is a router.
7. The device as claimed in claim 4 wherein the multi-port data communication device is a gateway.
8. The device as claimed in claim 1 further comprising at least 1000 Mb/s interfaces for communicative coupling to the at least four wire.
9. The device as claimed in claim 1 wherein the device is a multi-port data communication device.
10. The device as claimed in claim 9 wherein the multi-port data communication device is a switch.
11. The device as claimed in claim 9 wherein the multi-port data communication device is a router.
12. The device as claimed in claim 9 wherein the multi-port data communication device is a gateway.
13. The device as claimed in claim 1 wherein the device is configured to provide two simultaneous phantom channels using all of the four wire pairs.
14. The device as claimed in claim 1 wherein the at least four wire pairs is N wire pairs, and the device is configured to provide N−1 simultaneous phantom channels.
15. The device as claimed in claim 1 wherein the circuitry comprises telephone circuitry.
16. The device as claimed in claim 1 further comprising at least one female connector coupled to the secondary windings of at least two of the first, second, third and fourth transformers.
17. The device as claimed in claim 16 wherein the female connector is an RJ-45 data connector.
18. The device as claimed in claim 1 wherein the LAN further comprises a data unit couplable to the device, and the secondary windings of the first, second, third and fourth transformers provide four equipment side windings for the data unit.
19. The device as claimed in claim 1 wherein the phantom signal comprises power.
20. The device as claimed in claim 1 wherein the phantom signal comprises DC power.