A cellular phone which is capable of receiving/transmitting an e-mail detects whether or not the e-mail received includes a predetermined e-mail allotted to an inquiry sent from a sender prior to a telephone call. Responsive to the predetermined e-mail, the cellular phone automatically sends the sender a state e-mail which is indicative of a state of the cellular phone. The state of the cellular phone may specify whether or not the cellular phone is put into a receivable state of the telephone call. Responsive to the state e-mail, the sender may make a telephone call to the cellular phone with reference to the state of the cellular phone. The predetermined e-mail may include a predetermined password known by an exclusive number of persons while the state e-mail may be sent in consideration of schedule information stored in the cellular phone.