DR 2-102 (A) (5)
TELEPHONE DIRECTORY LISTINGS
A lawyer may list his telephone number in any telephone directory that includes the geographical area where he resides, where he maintains an office, and where a significant portion of his clientele resides. However, he may list no more than two telephone numbers unless he has more than one office in the geographical area covered by the telephone directory, in which event he can give one listing for each office.
An individual lawyer may be listed in both the alphabetical and classified sections of the telephone directory, or the directories, of the city in which his office is located. In addition, he may also properly be listed in both the alphabetical and classified sections of each directory which includes or covers any of the following geographical areas: The area in which the lawyer resides, the area in which he maintains an office, and the area in which a significant portion of his clientele resides. It is, therefore, the number of directory-covered geographical areas in which the lawyer has such contacts or relationships which determines the number of directory listings he may properly have. Directory listings should never be for the purpose of advertising or solicitation but should be for convenience of the public. What constitutes a significant part of the clientele of a lawyer is a question of fact to be determined in each case. (See Opinion 361). Directory listings may only be justified for the convenience of the public and may never be used for the purpose of advertising or solicitation.
A lawyer may list no more than two telephone numbers in any telephone directory unless he has more than one office in the geographical area covered by the telephone directory, in which event he can give one listing for each office.
Tex. Comm. On Professional Ethics, Op. 386 (1976)