In a digital cordless telephone set as a subsidiary unit, when both a radio wave from a radio base station connected to a public line and a radio wave from a master unit connected to a private line can be received, a sensor detects whether the subsidiary unit is placed on a charger. If the subsidiary...http://www.google.fr/patents/US6282432?utm_source=gb-gplus-shareBrevet US6282432 - Digital cordless telephone set
