US 5,889,856 A · ADSL integrated line card with digital splitter and POTS CODEC without bulky analog splitter

Abstract

An integrated line-card terminates an asymmetric digital-subscriber line (ADSL) copper-pair at a single point in a central office. The line card contains analog line circuitry such as a ring generator, off-hook detector, D.C. current feed, and a single analog-digital (A/D) converter. The phone line carries a composite signal of both the high-frequency ADSL data and the low-frequency voice or plain-old-telephone-service (POTS) signal. Instead of using an analog frequency-splitter with bulky, expensive inductor coils, a digital splitter is used. A digital-signal processor (DSP) can be used to perform the digital splitting of ADSL and POTS. The waveforms from the analog phone line are first converted to digital values by the A/D converter, and then a digital splitter separates the low-frequency POTS from the high-frequency ADSL. The ADSL data is formatted by the DSP for a data pathway to the Internet, while the POTS data is converted by the DSP to A-Law or C-Law for transmission over the telephone network's PCM highway. The DSP can perform all decoding, encoding, compression, and formatting needed by both ADSL and POTS. The quality of the phone line is improved by having a single termination point at the central office, rather than separate termination points for POTS and ADSL data from the phone line.

Claims22

Dependent claims

An integrated line card for terminating a phone line at a central office, the phone line connected to a customer premises, the integrated line card comprising:

a phone-line input for receiving an analog phone signal from the phone line, the analog phone signal having a high-frequency band for carrying data transmissions and a low-frequency band for transmitting voice calls from a customer telephone set at the customer premises;
an analog phone-line interface, coupled to the analog phone signal, for powering the phone line and generating ring tones over the phone line to ring the customer telephone set when an incoming call to the customer premises is received at the central office;
an analog-digital (A/D) converter, coupled to receive the analog phone signal, for converting the analog phone signal to a digital phone signal;
a digital splitter, coupled to receive the digital phone signal from the A/D converter, for separating the high-frequency band carrying the data transmissions from the low-frequency band transmitting the voice calls, the digital splitter outputting a high-frequency digital signal and a low-frequency digital signal;
a data-pathway interface, receiving the high-frequency digital signal from the digital splitter, for transmitting the data transmissions from the customer premises to a data pathway;
and
a voice-call highway interface, receiving the low-frequency digital signal from the digital splitter, for transmitting the voice call received from the customer premises to a voice-call highway to other central offices,
whereby the phone line is digitally split into high- and low-frequency signals to the data pathway and to the voice-call highway.

5 more elements

An asymmetric digital-subscriber line (ADSL) line card for terminating an ADSL phone line at a central office, the ADSL line card comprising:

an analog interface to a copper twisted-pair phone cable from a remote customer;
an analog-digital (A/D) converter, for converting analog voltages coupled from the copper twisted-pair phone cable to a composite digital signal representing the analog voltages, the A/D converter also converting incoming mixed digital signals to analog voltages for driving the copper twisted-pair phone cable;
a digital-signal processor (DSP), coupled to the A/D converter, for digitally filtering the composite digital signal to produce a high-frequency component and a low-frequency component, the high-frequency component being a representation of data transmissions over the copper twisted-pair phone cable while the lowfrequency component being a representation of a voice call from plain-old-telephone-service (POTS) equipment at the remote customer;
the DSP including data formatting means for formatting the high-frequency component to a data format for transmission over a high-speed data network to the Internet;
and
the DSP including voice-call encoding means for encoding the low-frequency component as pulse-code-modulated (PCM) data for transmission over a PCM highway for transferring voice calls to other central offices,
whereby the DSP digitally splits the high- and low-frequency components representing the data transmissions and the voice calls, and wherein an analog splitter at the central office is not used.

4 more elements

A digital-subscriber line (DSL) for transmitting voice calls and data over a phone line, the digital-subscriber line comprising:

customer-premises equipment, located at a remote end of the phone line, the customer-premises equipment including:
an analog frequency splitter, coupled to the phone line, for splitting low-frequency voice calls from high-frequency data;
a DSL modem, coupled to receive the high-frequency data from the analog frequency splitter, for demodulating the data for use by computer equipment at a customer premises;
a telephone set, coupled to receive the low-frequency voice calls from the analog frequency splitter, for receiving and sending voice calls, the telephone set being an ordinary plain-old-telephone-service (POTS) telephone set;
central-office equipment, located at a local end of the phone line, for transmitting and receiving data and voice calls from the phone line, a central office connected to other central offices, long-distance exchanges, and Internet-connection points, the central-office equipment including:
an analog-line interface, connected to the phone line, for powering the phone line, generating ring tones and detecting when the telephone set is off hook at the customer premises;
an analog-digital converter, coupled to the phone line, for converting data and voice calls from the phone line to a combined digital data-stream;
a digital splitter, receiving the combined digital data-stream, for frequency-filtering the combined digital data-stream to output a POTS data-stream of low-frequency components of the combined digital data-stream and to output a DSL data-stream from the high-frequency components of the combined digital data-stream;
a first encoder for encoding the POTS data-stream for transmission to conventional telephone switch to send voice calls to other central offices;
and
a data transmitter for transmitting the DSL data-stream to the Internet-connection points,
whereby the central-office equipment includes the digital splitter but the customer-premises equipment includes the analog frequency splitter.

9 more elements

Dependencies are inferred from the claim text.

ADSL integrated line card with digital splitter and POTS CODEC without bulky analog splitter

Life of this patent

ADSL integrated line card with digital splitter and POTS CODEC without bulky analog splitter

Life of this patent

Abstract

Claims22