(a) Examining witness concerning prior statement. In examining a witness
concerning a prior statement made by the witness, whether written or not, the
statement need not be shown nor its contents disclosed to the witness at that
time, but on request the same shall be shown or disclosed to opposing counsel.
(b) Extrinsic evidence of prior inconsistent statement of witness. Extrinsic
evidence of a prior inconsistent statement by a witness is not admissible unless
the witness is afforded an opportunity to explain or deny the same and the
opposite party is afforded an opportunity to interrogate the witness thereon, or
the interests of justice otherwise require. This provision does not apply to
admissions of a party-opponent as defined in Rule 801(d)(2).