
351 S.E.2d 138 (1986)
83 N.C. App. 647
STATE of North Carolina
v.
John Edward DARROW.
No. 8610SC441.
Court of Appeals of North Carolina.
December 30, 1986.
*139 Atty. Gen. Thornburg by Asst. Atty. Gen. Henry T. Rosser, Raleigh, for State.
Purser, Cheshire, Parker & Hughes by Gordon Widenhouse, Raleigh, for defendant-appellant.
EAGLES, Judge.
Defendant argues that the court erred in denying his motion to dismiss because the evidence was insufficient to show that he violated the terms of the agreement. We disagree.
Defendant was allowed to participate in the felony diversion program pursuant to an agreement with the State under G.S. 15A-1341(a). This probationary status, however, is a matter of grace, not of right. State v. Lombardo, 306 N.C. 594, 295 S.E.2d 399 (1982). Consequently, in probation revocation proceedings, grounds for revocation need not be proven beyond a reasonable doubt. State v. Duncan, 270 N.C. 241, 154 S.E.2d 53 (1967). Instead, the court may allow revocation of probation on evidence which is sufficient to satisfy the court, in its discretion, that defendant has violated a valid condition of his probation. State v. Ginn, 59 N.C.App. 363, 296 S.E.2d 825, disc. rev. denied, 307 N.C. 271, 299 S.E.2d 217 (1982).
Here, the trial court found that the State proved, by a preponderance of the evidence, that defendant made an obscene telephone call to Ms. Crane on both 14 September 1984 and 10 July 1985. Since defendant signed his agreement with the State on 5 September 1984, these findings would support the trial court's conclusion that defendant violated the terms of his agreement and that his removal from the felony diversion program was for just cause. Findings of fact which are supported by competent evidence are binding on appeal, State v. Dampier, 314 N.C. 292, 333 S.E.2d 230 (1985), even if there is evidence to the contrary. State v. Small, 293 N.C. 646, 239 S.E.2d 429 (1977).
Examining the record, we find that the trial court's findings are fully supported by the evidence. Ms. Crane testified that she received an obscene telephone call on each of the dates in question. She testified that she was familiar with defendant's voice and that she recognized the voice of the caller as being defendant's. She further testified that she spoke with defendant for several minutes during each of the calls and that he used obscene language, attempted to convince her to engage in sexual acts with her, and told her that he was coming over to her home.
Defendant argues, however, that Ms. Crane's testimony was incredible. First, defendant claims that his evidence establishes an alibi on each of the two occasions she reported receiving a call. *140 Second, defendant argues that the testimony of his witnesses show that, due to changes in his voice, Ms. Crane could have been mistaken as to the identity of her caller. Defendant's evidence clearly conflicts with Ms. Crane's testimony. This does no more, however, than raise an issue of credibility, which in this proceeding is a question for the trial court to decide. State v. Booker, 309 N.C. 446, 306 S.E.2d 771 (1983). Ms. Crane's testimony regarding her familiarity with defendant's voice, and the length at which she spoke with the caller, serves as a sufficient basis from which the court could believe her identification of the caller. The trial court's finding of fact that defendant made obscene phone calls to Ms. Crane is adequately supported by the evidence.
Defendant next argues that the trial court erred in admitting testimony by Ms. Crane regarding the events which resulted in defendant's arrest and charge of burglary. His objection include Ms. Crane's testimony about an open copy of "Playboy" magazine which she found in a closet after defendant had allegedly broken into her home. Assuming, arguendo, that the evidence objected to was inadmissible under our rules of evidence, defendant has, nevertheless, failed to show any prejudicial error. The trial court, in probation revocation proceedings, is not bound by strict rules of evidence. State v. Duncan, supra; State v. Coleman, 64 N.C.App. 384, 307 S.E.2d 207 (1983). Moreover, where the trial court, sitting without a jury, admits both competent and incompetent evidence, it will be presumed that the court relied on only the competent evidence and disregarded the incompetent evidence. State v. Baines, 40 N.C.App. 545, 253 S.E.2d 300 (1979). Defendant has failed to show anything to overcome this presumption. The trial judge stated that he was admitting the evidence only as background information and his findings, as already noted, are fully supported by competent evidence.
No error.
ARNOLD and JOHNSON, JJ., concur.
