Abstract: A portable battery-operated communication device includes a high-speed communication bus, a first high-speed communication processor coupled to the bus and configured for transferring communication signals to a second high-speed communication processor over the bus, and an isolation circuit for the bus with a first terminal coupled to the bus and configured to receive a first communication signal from the first processor via the bus, and a first resistor that is coupled to the first terminal and configured to protect the first terminal from an overcurrent failure condition, in which the isolation circuit is configured to match impendences between the isolation circuit and bus, isolate series inductance associated with the first terminal, protect the first terminal from an overvoltage failure while maintaining signal integrity of the first communication signal, and pass through the first communication signal from the first terminal to a second terminal coupled to the high-speed communication bus.

Abstract: A portable battery-operated communication device includes a high-speed communication bus, a first high-speed communication processor coupled to the bus and configured for transferring communication signals to a second high-speed communication processor over the bus, and an isolation circuit for the bus with a first terminal coupled to the bus and configured to receive a first communication signal from the first processor via the bus, and a first resistor that is coupled to the first terminal and configured to protect the first terminal from an overcurrent failure condition, in which the isolation circuit is configured to match impendences between the isolation circuit and bus, isolate series inductance associated with the first terminal, protect the first terminal from an overvoltage failure while maintaining signal integrity of the first communication signal, and pass through the first communication signal from the first terminal to a second terminal coupled to the high-speed communication bus.

Abstract: A portable battery operated communication device provides a device interface formed of a plurality of exposed device contacts including a live voltage contact and a GND contact. Electronic circuitry associated with the interface is configured to operate in a non-linear mode using a low leakage path in response to electrolytic contamination across the two contacts. The interface is further configured to operate in a linear mode using a low current path during accessory attachment. Accessory detection is provided by a non-linear impedance device and sensor.