An information processing device capable of accepting a communication request from another information processing device without fail, regardless of whether the device is in a standby state or not. A first condition detection circuit detects, synchronously with a clock signal, a communication start condition for starting communication with the other information processing device, and a second condition detection circuit detects, asynchronously with the clock signal, the communication start condition for starting communication with the other information processing device. A selector circuit selects a suitable one of the first and second condition detection circuits.