Patent ID: 6603808
Filing Date: 2003-08-05
Classification: H04L

Abstract:
A computer system, comprising:a central processing unit; a memory array coupled to said central processing unit; an expansion bus coupled to said central processing unit and said memory array, said expansion bus capable of interfacing peripheral devices; and a networking modem coupled to said expansion bus, comprising: an expansion bus interface coupled to said expansion bus; a network interface capable of connecting to a telephone line; a programmable digital signal processor coupling said expansion bus interface to said network interface; said networking modem is capable of full duplex communication over the telephone line; wherein said computer system is capable of using said networking modem to communicate with another device connected to the telephone line; wherein said networking modem further comprises: a CODEC disposed between said network interface and said digital signal processor, said CODEC comprising an analog to digital converter that converts analog signals received through said network interface into incoming digital data and applies the incoming digital data to said digital signal processor and a digital to analog converter that converts digital data output from said digital signal processor into outgoing analog signals and applies the outgoing analog signals to the telephone line through said network interface; a digital phase locked loop that recovers the timing of a received pulse position modulation canrier; a carrier detector that asserts a carrier detect signal when said networking modem receives a pulse position modulated carrier; and a counter synchronized to said digital phase locked loop, wherein said counter counts when the carrier detect signal is deasserted; wherein said digital signal processor demiodulates a digital data signal received from the telephone line, and wherein the digital modulation comprises at least one of the following: pulse position modulation, pulse amplitutde modulation, quadratlire amplitude modulation, phase shift keying, and quadrature phase shift keying.