Line interface unit with feedback control

A system, comprising:

• line interface unit (LIU) circuitry, including a line output configured to output respective output waveforms of multiple instantiations of the LIU circuitry to a telecommunications line;
• a first instantiation of the multiple instantiations of the LIU circuitry, wherein the first instantiation of the LIU circuitry includes:
• a first transmit part, comprising:
• a first feedback controller configured to modify a first output waveform to fit a mask of a first communication protocol, the modification resulting in a second output waveform that fits the mask of the first communication protocol;
• and
• a second instantiation of the multiple instantiations of the LIU circuitry, wherein the second instantiation of the LIU circuitry includes:
• a second transmit part, comprising:
• a second feedback controller configured to modify a third output waveform to fit a mask of a second communication protocol, the modification resulting in a fourth output waveform that fits the mask of the second communication protocol.

A system comprising:

• input/output circuitry, comprising:
• line interface unit (LIU) circuitry configured to:
• drive telecommunications signals on a telecommunications line;
• and
• derive multiple instantiations of itself, each of the multiple instantiations corresponding to a respective communications protocol and including:
• an analog part;
• and
• a digital part, comprising:
• a digital state machine configured to:
• convert a first electromagnetic signal into a second electromagnetic signal representative of a sequence of samples according to, in part, feedback of a feedback controller of the analog part;
• and
• communicate the sequence of samples to the analog part,
• the analog part, comprising:
• a digital-to-analog converter configured to convert the sequence of samples into an analog differential electromagnetic signal;
• a line driver configured to communicate the analog differential electromagnetic signal to the telecommunications line;
• and
• the feedback controller, the feedback controller configured to output the feedback according to the analog differential electromagnetic signal and a reference signal that fits a mask of the communication protocol.