Patent ID: 8847730

Claim:
A vehicular keyless entry system comprising: a plurality of portable devices; and an in-vehicle device for performing checkup about the plurality of portable devices and a vehicle door locking control operation, wherein the in-vehicle device includes a plurality of antennas provided for checking up the plurality of portable devices, and a checkup unit, which causes the plurality of antennas to transmit area identification signals including checkup area identification information in response to an instruction of starting a vehicle door locking control operation, the checkup area identification information being different among checkup areas; wherein each of the plurality of portable devices is configured to store the checkup area identification information of all of received area identification signals in response to reception of the area identification signals from the in-vehicle device, wherein each of the plurality of portable devices are configured to transmit a response signal including portable device identification information thereof, which is different among the portable devices, and all stored checkup area identification information, when a request signal is received from the in-vehicle device; wherein the checkup unit is configured to cause the plurality of antennas to transmit request signals to the plurality of portable devices after transmission of the area identification signals, and configured to check up the plurality of portable devices based on the portable device identification information included in the response signals transmitted from the portable devices, which received the request signals, and determines location of the plurality of portable devices based on the checkup area identification information included in the response signals; wherein the checkup unit is further configured to perform a vehicle door locking control operation based on checkup results of the portable device checkup part; wherein the portable device includes a memory circuit, a memory control circuit for storing in the memory circuit the checkup area identification information included in each of the area identification signals upon reception of the area identification signals from the plurality of antennas, and a transmitter circuit for transmitting the response signal upon receipt of the request signal from the in-vehicle device, the response signal including the portable device identification information for identifying the portable device and all the checkup area identification information stored in the memory circuit; and wherein the memory control circuit is configured to erase all the checkup area identification information stored in the memory circuit when the response signal is transmitted from the transmitter circuit.