US 6,785,340 B1 · PCM upstream and downstream system for universal digital loop carrier

Abstract

A central office line unit (COLU) for a pulse code modulation (PCM) upstream and downstream system in a universal digital loop carrier (UDLC) includes a hybrid circuit for transmitting/receiving an analog signal to/from a switch. An analog-to-digital converter is provided for receiving the analog signal from the hybrid circuit and converting the analog signal to a converted digital signal. A digital transmission circuit transmits/receives a digital signal to/from a remote terminal. A quantizer is provided for evaluating and processing the converted digital signal so that only valid states of the converted digital signal are transmitted to the digital transmission circuit for transmission to the remote terminal. A receiver is used for receiving the digital signal from the digital transmission circuit and for evaluating and processing the digital signal so that only valid states of the digital signal are outputted from the receiver. A transmitter receives the digital signal from the receiver and equalizes the digital signal. And, a digital-to-analog converter converts the equalized digital signal to a converted analog signal and transmits the converted analog signal to the hybrid circuit, which transmits the converted analog signal to the switch.

Claims44

Dependent claims

A central office line unit (COLU) for a pulse code modulation (PCM) upstream and downstream system in a universal digital loop carrier (UDLC), comprising:

a hybrid circuit for sending and receiving an analog signal to and from a switch;
an analog-to-digital converter for receiving the analog signal from the hybrid circuit and converting the analog signal to a converted digital signal;
a digital transmission circuit for sending and receiving a digital signal to and from a remote terminal;
a quantizer for evaluating and processing the converted digital signal so that only valid states of the converted digital signal are transmitted to the digital transmission circuit for transmission to the remote terminal;
a receiver for receiving the digital signal from the digital transmission circuit and for evaluating and processing the digital signal so that only valid states of the digital signal are outputted from the receiver;
a transmitter for receiving the digital signal from the receiver and for equalizing the digital signal;
and
a digital-to-analog converter that converts the equalized digital signal to a converted analog signal and transmits the converted analog signal to the hybrid circuit, which transmits the converted analog signal to the switch.

5 more elements

A pulse code modulation (PCM) upstream and downstream system in a universal digital loop carrier (UDLC), comprising:

at least one analog modem connected to an analog plain old telephone system (POTS) line;
a remote terminal connected to the analog modem via the analog POTS line and further connected to a high-speed digital subscriber line;
a central office line unit including,
a hybrid circuit for sending and receiving an analog signal to and from a switch, wherein the switch is connected to the hybrid circuit via a second analog plain old telephone system (POTS) line,
an analog-to-digital converter for receiving the analog signal from the hybrid circuit and converting the analog signal to a converted digital signal,
a digital transmission circuit for sending and receiving a digital signal to and from the remote terminal,
a quantizer for evaluating and processing the converted digital signal so that only valid states of the converted digital signal are transmitted to the digital transmission circuit for transmission to the remote terminal,
a receiver for receiving the digital signal from the digital transmission circuit, and for evaluating and processing the digital signal so that only valid states of the digital signal are outputted from the receiver,
a transmitter for receiving the digital signal front the receiver, and for equalizing the digital signal, and
a digital-to-analog converter that converts the equalized digital signal to a converted analog signal and transmits the converted analog signal to the hybrid circuit, which transmits the converted analog signal to the switch via the second analog POTS line;
and
a digital modem connected to the switch via a digital serial data link line.

9 more elements

Dependencies are inferred from the claim text.

PCM upstream and downstream system for universal digital loop carrier

Life of this patent

PCM upstream and downstream system for universal digital loop carrier

Life of this patent

Abstract

Claims44