PURPOSE: To easily and surely attain holding transfer of a call arrived from an external line between cordless slave sets by displaying the operating state of the caller side cordless slave set on the called party cordless slave set.

CONSTITUTION: A radio connection request signal is sent from a caller cordless slave set 12 and a cordless master set 10 receiving the signal sends a radio connection enable signal and a slave set identification number '1' signal. A green LED 37 is lighted on the cordless slave set 12 because the slave set identification number '1' signal matches. Since the slave set identification number '1' does not match in the cordless slave set 11, a red LED 27 is lighted. Then, the user observing the lighting state makes holding and transfer from the cordless slave set 12 to the cordless slave set 11.