3com Corporation

Randy C Rollins

Tim Urry Price

Scott W Rupp

Kurt Dobson

Michael R Fine

Kenneth Morely

Phil Adams

A novel line-current protection circuit for detecting excessive line current from a telephone line and protecting line interface circuitry from the excessive line current is presented. The protection circuit is adapted to detect when an excessive current is present on the tip and ring lines indicative of the misconnection of the modem or other line interface device with a telephone network that presents an incompatible interface standard. The preferred embodiment appreciates the multimode hold current specifications throughout the world and evaluates the connection of the line interface circuit with a telephone line to determine the compatibility therewith. When excessive line current is detected, the line-protection circuit switches the vulnerable line interface out of the circuit. When compatible line current levels are detected, the present invention reconfigures the configurable hold circuit into its original operating (e.g., non-testing) state for call processing.

Line current protection circuit and method for linear and nonlinear hold circuit

In order to boot a portable computer, a smart key is required to be inserted into a PCMCIA card of the portable computer. Firmware in the PCMCIA card verifies that a smart key has been inserted. The portable computer will boot only when two conditions are met. The first condition is that the smart key, the PCMCIA card, and the portable computer all contemporaneously have the matching codes stored therein. The second condition is that the first condition is met and that a new random generated and encrypted code is successfully stored in each of the smart key, the PCMCIA card, and the portable computer. Until these two conditions are met, the portable computer will not boot. Once booted, access to certain coded files on the portable computer is denied if respective matching codes in the coded files are not also contained in the smart key. Also, the portable computer will not exit an idle, sleep, or power conservation mode until the two conditions are met. Also disclosed are an inventive apparatus and system including a smart key, an ASIC analogous to the PCMCIA card, and a computerized apparatus analogous to the portable computer, where the foregoing two conditions must be met before a user gains access to the computerized apparatus. Contemplated computerized apparatus include PDAs, copy machines, facsimile machines, standalone modems, mobile telephones, pagers, televisions, and automobiles.

Security system for a computerized apparatus

A peripheral module capable of interaction with a host system comprises a digital signal processor (DSP), a cache controller, and minimal or no resident memory for initial storage of instructions and data. The peripheral module utilizes the memory resources (e.g., ROM and RAM) of a host system. The cache controller interfaces to the DSP and provides an instruction and data stream, upon request, from a resident cache. A bus interface unit arbitrates access to the host system via a host bus for access to host system resources by the cache controller for extracting DSP information (e.g., instructions and data) from the host system for utilization by the DSP within the peripheral module. The cache controller and cache thereby provide the instruction and data stream as required by the DSP for digital signal processing applications and relieve the need for resident storage within the peripheral module.

Growing community of inventors

West Jordan, UT, United States of America

Randy C Rollins