(b) Petitioner in all probability entertained no actual expectation of privacy in the phone numbers he dialed, and even if he did, his expectation was not "legitimate." First, it is doubtful that telephone users in general have any expectation of privacy regarding the numbers they dial, since they typically know that they must convey phone numbers to the telephone company and that the company has facilities for recording this information and does in fact record it for various legitimate business purposes. And petitioner did not demonstrate an expectation of privacy merely by using his home phone rather than some other phone, since his conduct, although perhaps calculated to keep the contents of his conversation private, was not calculated to preserve the privacy of the number he dialed. Second, even if petitioner did harbor some subjective expectation of privacy, this expectation was not one that society is prepared to recognize as "reasonable." When petitioner voluntarily conveyed numerical information to the phone company and "exposed" that information to its equipment in the normal course of business, he assumed the risk that the company would reveal the information
[442
U.S. 735, 736]
to the police, cf. United States v. Miller,
425
U.S. 435
. Pp. 741-746.
283 Md. 156, 389 A. 2d 858, affirmed.