Abstract: A compact low-power radio frequency (RF) transceiver with a built-in antenna provides wireless communication between a computer and another device. A direct conversion receiver together with a voltage controlled oscillator, phase lock loop circuits, digitally controlled divider circuits and a patch antenna are packaged into a compact enclosure, having dimensions within the PCMCIA format. In some embodiments, the transceiver enters a sleep mode whenever it is idle in order to further conserve power. In other embodiments, a signature detector enables the transceiver to distinguish between noise and valid messages by recognizing a signature word embedded in the data packet.