Line-powered network interface device
View Patent ↗A network interface device includes a first interface, a power extractor, a transceiver, and a second interface. The first interface receives a signal that includes both power and packetized information. The power extractor extracts the power from the signal and powers the transceiver. The transceiver extracts the packetized information from the signal and communicates the information to a user device using the second interface.
1. A network interface device, comprising:
a first interface operable to receive a signal from a local loop circuit, the signal comprising power and packetized information;
a power extractor operable to extract the power from the signal;
a transceiver powered by the power extractor and operable to extract the information from the signal;
a second interface operable to communicate the information to a user device;
a ring generator operable to produce a ring signal for the user device, the ring generator comprising:
a pulse modulator operable to generate a digital output signal in response to an input signal;
a first output transistor operable to produce a first output voltage for a first duration determined based on an amplitude of the input signal;
a second output transistor operable to produce a second output voltage for a second duration determined based on the amplitude of the input signal;
a switch operable to switch between the first output transistor and the second output transistor in response to a zero crossing in the input signal; and
a low-pass filter operable to convert output of the output transistors into an analog signal; an
an automatic gain controller operable to:
monitor a power level of the analog signal; and
adjust an amplification level of the digital output signal based on the power level of the analog signal.
2. The device of claim 1 , further comprising:
a housing enclosing the power extractor and the transceiver; and
wherein the housing is securable to an exterior wall of a building.
3. The device of claim 1 , further comprising:
a processor operable to trigger the ring generator; and
a memory operable to store the information extracted from the signal during ringing of the user device.
4. The device of claim 3 , wherein:
the second interface is coupled to a plurality of user devices; and
the processor is further operable to trigger the ring generator to ring the user devices in succession.
5. The device of claim 1 , wherein:
the transceiver comprises DSL modulation and demodulation circuitry; and
the signal is a modulated DSL signal.
6. The device of claim 1 , wherein the local loop circuit comprises a twisted pair line.
7. A network interface device, comprising:
a first interface coupled to a twisted pair line and operable to receive a modulated DSL signal comprising packetized information and power;
a power extractor operable to extract the power from the signal;
a transceiver comprising DSL modulation and demodulation circuitry operable to demodulate the modulated DSL signal to extract the packetized information;
a second interface operable to communicate the packetized information to a user device;
a housing enclosing the first interface, the power extractor, the transceiver and the second interface, the housing adapted to be secured to a building; and
a ring generator comprising:
a pulse modulator operable to generate a digital output signal in response to an input signal;
a first output transistor operable to produce a first output voltage for a first duration determined based on an amplitude of the input signal;
a second output transistor operable to produce a second output voltage for a second duration determined based on the amplitude of the input signal;
a switch operable to switch between the first output transistor and the second output transistor in response to a zero crossing in the input signal; and
a low-pass filter operable to convert output of the output transistors into an analog signal; and
an automatic gain controller operable to:
monitor a power level of the analog signal; and
adjust an amplification level of the digital output signal based on the power level of the analog signal.
8. The device of claim 7 , further comprising:
a memory operable to store the information extracted from the DSL modulated signal; and
a processor operable to:
trigger the ring generator to produce a ringing signal for the user device; and
communicate the information to the user device after the ringing signal is communicated to the user device.
9. The device of claim 8 , wherein:
the second interface is coupled to a plurality of user devices; and
the processor is further operable to trigger the ring generator to generate a ringing signal for each of the plurality of user devices in a predetermined sequence.
10. The device of claim 7 , wherein the transceiver is operable to encode and decode information in accordance with the ATM Forum's Broadband Loop Emulation Standard (BLES).