http://www.rfc-editor.org/rfc/rfc2243.txt
RFC 2243: OTP Extended Responses, C. Metz1997-11-01T23:00:00-00:00This document provides a specification for a type of response to an OTP [RFC 1938] challenge that carries explicit indication of the response's encoding. This document also provides a specification for a response that allows an OTP generator to request that a server re-initialize a sequence and change parameters such as the secret pass phrase. [STANDARDS-TRACK]