Method and system for providing DC power on local telephone lines
View Patent ↗A system for providing DC power on local telephone lines, such as telephone lines in a building or office, for powering devices and circuitry associated with communications over those telephone lines, as well as other functions. Desired voltage and power levels are supplied over local telephone lines by separating the DC power component from the central office or private branch exchange with a DC blocking filter while passing all AC telephony signals. A distinct DC power is then imposed over the telephone line for powering both the telephony service as well as other loads. Conventional telephone off-hook detection is simulated for compatibility with the central office or private branch exchange. The functions required may be integrated, partially or fully within a telephone outlet.
1. A network for carrying analog telephone, power and data signals, the network comprising:
a single wire pair concurrently carrying a DC power signal, an analog telephone signal and a bi-directional digital data signal, wherein the analog telephone signal and the bi-directional digital data signal are carried using frequency division multiplexing, with the digital data signal being carried in a digital data signal frequency band and the analog telephone signal being carried in an analog telephone signal frequency band lower than the digital data signal frequency band;
a central office-side unit connected to said single wire pair for coupling a central office-side telephone signal to the analog telephone signal, for converting a power source signal to the DC power signal, and for coupling a data network to the bi-directional digital data signal; and
a subscriber-side unit connected to said single wire pair, said subscriber-side unit comprising:
a telephone connector connectable to an analog telephone set for coupling the analog telephone set to the analog telephone signal, and
a data port couplable to a data unit for coupling the data unit to the bi-directional digital data signal,
wherein the subscriber-side unit is at least in part powered by the DC power signal.
2. The network according to claim 1 , wherein the DC power signal voltage is distinct from a −43 volt DC analog telephone signal, and the subscriber-side unit further comprises a DC to DC voltage converter to convert the DC power signal voltage to a −43 volt DC telephony signal.
3. The network according to claim 1 , wherein the bi-directional digital data signal is DSL based.
4. The network according to claim 1 , wherein the subscriber-side unit further comprises a power port for DC power feeding of a device that is different from a telephone set, the power port being coupled to receive the DC power signal.
5. The network according to claim 1 , wherein the subscriber-side unit further comprises a current limiter coupled to the telephone connector for continuously limiting the current available to the analog telephone set.
6. The network according to claim 1 , wherein the subscriber-side unit is further attached to a wall.
7. The network according to claim 1 , wherein the subscriber-side unit is at least in part housed within an outlet.
8. The network according to claim 1 , wherein an off-hook state signaling of an analog telephone set connected to the telephone connector is carried over the wire pair as a tone.
9. The network according to claim 1 , wherein an off-hook state signaling of an analog telephone set connected to the telephone connector is carried over the wire pair as part of the bi-directional digital data signal.
10. The network according to claim 1 , wherein the wire pair is part of a subscriber loop.
11. The network according to claim 10 , wherein the central office-side unit is located at a PSTN exchange and the subscriber-side unit is located at a subscriber location.
12. The network of claim 1 , wherein the digital data signal is packet-based and said data port is a bi-directional packet-based digital data port.
13. The network of claim 12 , wherein said data port conforms to one of an IEEE802.3, 10/100BaseT and USB standard.
14. The network of claim 1 , wherein the analog signal is an unmodulated voice frequency signal and said units are constructed to transmit that signal between said units.
15. The network of claim 1 , wherein said central office-side unit is operative to produce the DC power signal continuously.
16. A device for coupling an analog telephone signal to an analog telephone set and for coupling a digital data signal to a data unit, for use with a single wire pair carrying analog telephone, bi-directional digital data and a DC power signal, the analog telephone signal and the digital data signal being carried using frequency division multiplexing, with the digital data signal being carried in a digital data signal frequency band and the analog telephone signal being carried in an analog telephone signal frequency band lower than the digital data signal frequency band, the device comprising:
a wiring connector for connecting to the wire pair;
a low pass filter coupled to said wiring connector for passing the analog telephone signal;
a telephone connector coupled to the low pass filter and connectable to an analog telephone set, for coupling the analog telephone signal to the analog telephone set;
a high pass filter coupled to said wiring connector for passing the digital data signal;
a modem coupled to said high pass filter for coupling to the digital data signal; and
a data port couplable to a data unit for coupling the digital data signal to the data unit, wherein the device is at least in part powered by the DC power signal.
17. The device according to claim 16 , wherein the DC power signal voltage is distinct from a −48 volt DC analog telephone signal, and the device further comprises a DC to DC voltage converter coupled to the wiring connector and operative to convert the DC power signal voltage to a −48 volt DC analog telephone signal.
18. The device according to claim 16 , wherein modem is a DSL based modem.
19. The device according to claim 16 , further comprising a power port for DC power feeding of a different device, the power port being coupled to the wiring connector for coupling to the DC power signal.
20. The device according to claim 16 , further comprising a current limiter coupled to the telephone connector and operative to continuously limit the current available in the telephone connector.
21. The device according to claim 16 , wherein the device is further attachable to a wall.
22. The device according to claim 16 , wherein the device is at least in part housed within an outlet.
23. The device according to claim 16 , wherein an off-hook state signaling of an analog telephone set connected to the telephone connector is converted to a tone that is coupled to the wiring connector.
24. The device according to claim 16 , wherein an off-hook state signaling of an analog telephone set connected to the telephone connector is part of the bi-directional digital data signal and is coupled to the wiring connector.
25. The device of claim 16 , wherein the digital data signal is packet-based and said data port is a bi-directional packet-based digital data port.
26. The device of claim 25 , wherein said data port conforms to one of an IEEE802.3, 10/100BaseT and USB standard.