Pulse or digital communications – Miscellaneous
Reexamination Certificate
1995-12-29
2001-10-02
Tse, Young T. (Department: 2634)
Pulse or digital communications
Miscellaneous
C345S168000, C341S024000, C341S026000, C379S368000, C084S655000
Reexamination Certificate
active
06298107
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to electronic communications, and more particularly, to a narrowband digital cordless telephone baseband chip for use in a hand unit or base unit of a digital cordless telephone.
Typical cordless telephones are known in the art. Advances in cordless telephony are continually being made, however, and those advances are often significant. Certain types of cordless telephones may operate digitally. Those digital cordless telephones may provide greater quality and capabilities than analog devices.
Cordless telephones are popular with residential and individual consumers. As cordless telephone technology advances, cordless telephones may prove advantageous to other consumers as well, such as businesses and commercial groups. When cordless telephones are designed for the lower-end residential and individual consumer market, price and quality are primary considerations of those consumers. Digital telephones tend to provide greater quality of sounds and capabilities than analog telephones. It is desirable, therefore, that a digital cordless telephone of good quality and adequate capabilities be available to that lower-end market.
In addition to quality, the cordless telephone market is particularly price conscious. Low-end consumers, such as residential and individual users, particularly look for economy. Although various designs of digital cordless telephones may be available, those designs have not adequately met the consumer's need for quality as well as economy. A digital cordless telephone that meets those expectations of consumers, thus, would provide significant improvement and advance in the technology.
Beyond those two expectations of quality and economy of cordless telephone consumers, residential and individual cordless telephone users must typically operate within a narrow bandwidth. Such a narrow bandwidth presents problems that must be addressed by digital cordless telephone designers. For example, within the narrow bandwidth, multiple users may need to simultaneously communicate. In order to avoid interference among users and inaccurate communications in those cases, designs of digital cordless telephones must provide for multiple users. The designs must also meet the market requirements of quality and low price.
Prior cordless telephones required the software of the phone to guess which key was intended when a user hit multiple keys on different rows or columns. The software often guessed the wrong number, or interpreted the action as neither key being pressed, resulting in either an incorrect phone number being dialed, or no phone number being dialed.
Therefore, what is needed is an economical and quality digital cordless telephone which enables desired communications over a narrow bandwidth, and which does not require the telephone software to guess about keypad switch closures.
SUMMARY OF THE INVENTION
In one embodiment, the invention is a digital cordless telecommunications unit that receives and transmits analog voice signals. In addition, the unit 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.
REFERENCES:
patent: 5717343 (1998-02-01), Kwong
patent: 6125139 (2000-09-01), Hendrickson et al.
Legerity Inc.
Tse Young T.
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