Narrowband digital cordless telephone

A baseband device for use with a digital cordless telecommunications unit, the baseband device comprising:

• an audio interface for externally transmitting an analog audio signal;
• a digital interface for receiving a digital baseband data signal, wherein the digital baseband data signal includes a voice channel and a control channel;
• a protocol functions block connected to the digital interface and including a frame formatter for receiving the digital baseband data signal, the frame formatter comprising means for repeatedly extracting control data bits and digital voice data bits from the control channel and voice channel, respectively, of the received digital baseband data signal, wherein the control data bits and digital voice data bits are interleaved at a rate optimized for 32 kilobit per-second adaptive differential pulse code modulator (ADPCM) data;
• an audio functions block connected to the audio interface and to the protocol functions block, the audio functions block comprising an ADPCM codec for receiving the digital voice data from the frame formatter and converting the digital voice data to the analog audio signal to be transmitted by the audio interface;
• a FIFO buffer coupled to the codec adapted for storage of data words received from an external device and output of the data words to the codec the FIFO buffer including means for determining if there is overflow of data words in the buffer and means for discarding a data word from the buffer in response to the overflow, and thereby avoiding a disruption of synchronous communication;
• and
• a system control function block including a microcontroller for controlling certain features of the baseband device and an interrupt controller connected between the microcontroller and the protocol functions block for receiving the control data from the frame formatter and controlling operation of the microcontroller in response thereto.

A method for interfacing transmit and receive digital baseband data signals with transmit and receive analog audio signals for use in a digital cordless telephone, comprising the steps of:

• determining and extracting a receive control data and a receive digital voice data from the receive digital baseband data signal according to a synchronization data provided in the receive digital baseband data signal and according to an interleaving pattern optimized for adaptive differential pulse code modulator (ADPCM) codec data;
• storing data words received from an external device in a FIFO buffer:
• determining if there is an overflow of data words in the buffer:
• discarding a data word from the buffer in response to overflow, thereby avoiding a disruption of synchronous communication;
• outputting data words from the FIFO to the codec;
• supplying the receive digital voice data to an ADPCM codec;
• converting the receive digital voice data to the transmit analog audio signal with the ADPCM codec;
• supplying the receive control data to a microcontroller to instruct the microcontroller to control predetermined features of the digital cordless telephone;
• converting the receive analog audio signal to a transmit digital voice data with the ADPCM codec;
• supplying the transmit digital voice data to a frame formatter;
• supplying a first and second transmit control data from the microcontroller to the frame formatter;
• and
• combining the first transmit control data and the transmit digital voice data in the frame formatter according to the second transmit control data and according to the interleaving pattern to form the transmit digital baseband data signal;
• wherein the receive control data instructs the microcontroller by requesting interrupts of the microcontroller;
• and
• wherein the frame formatter adapts to multiple formats of the receive digital baseband data signal.

A digital cordless telecommunications unit for communicating analog receive and transmit voice signals and for communicating digital baseband receive and transmit signals between a base unit and a portable unit, comprising:

• an analog front end and an adaptive pulse code modulator (ADPCM) codec, the analog front end and the ADPCM codec adapted to process the analog receive and transmit voice signals;
• a frame format circuit adapted to format signals and to enable synchronous communications between the base unit and the portable unit;
• a system control functions circuit including a microcontroller arrangement and adapted to control the communications between the base unit and the portable unit;
• a memory circuit adapted to buffer data between the analog front end and the ADPCM codec, wherein, in response to an overflow of data in the memory circuit, at least one data word is discarded from the memory circuit and in response to an underflow of data in the memory circuit, at least one data word is inserted to the memory circuit.

A digital cordless telecommunications unit for communicating analog receive and transmit voice signals and for communicating digital baseband receive and transmit signals between a base unit and a portable unit, comprising:

• an analog front end and codec means for modulating and demodulating data, the analog front end and the codec means adapted to process the analog receive and transmit voice signals;
• means for formatting the voice signals and digital baseband signals and for enabling synchronous communications between the base unit and the portable unit;
• means, including a microcontroller arrangement, for controlling the communications between the base unit and the portable unit;
• a memory circuit adapted to buffer data between the analog front end and the codec means, wherein, in response to an overflow of data in the memory circuit, at least one data word is discarded from the memory circuit and in response to an underflow of data in the memory circuit, at least one data word is inserted in the memory circuit.