In People v. Kreiling (1968) 259 Cal. App. 2d 699, the defendant, a former telephone repairman, opened up a pay phone and tripped a relay therein so he could make a free long-distance call. This prevented the phone from being used to make or receive other calls, until another repairman came and fixed it. ( Kreiling, supra, at p. 701.) As a result, the defendant was convicted of violating section 591. ( Kreiling, supra, at p. 700.) On appeal, the defendant argued that section 591 applied "solely to obstruction or interference with a telephone line as distinguished from the telephone instrument itself. He pointed out that section 591, as it was initially enacted in 1872, was in turn based on an 1862 statute concerned with physical destruction of telegraph lines and appurtenances to such lines." ( People v. Kreiling, supra, 259 Cal. App. 2d at p. 704, fn. omitted.) The court responded: "The amendments to section 591 since the date of its original enactment have substantially changed the definition of the offense. The statute as it is presently written is not confined to telephone or telegraph lines. It encompasses conduct by which the transmission of telephone and telegraph messages is interrupted by any of the enunciated methods. One who tampers with a telephone instrument in such way as to preclude its use for receiving or placing calls 'obstructs . . . any line of . . . telephone . . . or apparatus connected therewith' as effectively as if he physically severed the telephone line." (Ibid.)