Patent Number: 6,298,107

Title: Narrowband digital cordless telephone with a logic high weak driver and a logic low strong driver for keypad interface

Abstract: A digital cordless telecommunications unit that serves for communications when paired with a similar unit and connected with a network is disclosed. The unit receives and transmits analog voice signals and also transmits digital baseband signals and receives digital formatted baseband signals. The unit includes a baseband chip, as well as an audio functions block and a system control functions block. The audio functions block comprises an audio front end for receiving and transmitting the analog voice signals and an adaptive differential pulse code modulator codec, connected to the audio front end. The codec converts the analog voice signals to the digital baseband signals and converts the digital formatted baseband signals to the analog voice signals for transmission. The system control functions block comprises a microcontroller connected to the codec for controlling the baseband chip, a memory accessible by the microcontroller for storing control instructions, an interrupt controller connected to the microcontroller, a parallel port connected to the interrupt controller, a wake-up timer connected to the interrupt controller, a clock generator connected to the microcontroller, and a synchronous serial port connected to the interrupt controller.

Inventors: Mullins; Jacqueline (Austin, TX)

Assignee: Legerity, Inc.

International Classification: H03M 11/02 (20060101); H03K 017/94 ()

Expiration Date: 10/02/2018