D.2 The scope of applicability
23.0403GPPRelease 17Technical realization of the Short Message Service (SMS)TS
The reply procedures in clauses 5 and 6 of this annex should be followed by every MS which fulfils the following criteria:
1) The MS automatically selects the value for the RP‑Destination‑Address parameter in RP‑MO‑DATA, or the MS has the SC address within the SM‑RL entity. (That is to say: the human user is not obliged to manually key in the SC address for every MO short message).
2) The MS or an application within it supports some form of replying to a MT SM with a MO SM. (That is to say: in the process of generating the reply MO SM, any reference whatsoever, implicit or explicit, is made to the original MT SM).
3) The replying support of (2) is to be equally available towards every SME.
When an SME submits an SM to an SC for delivery, it may request that the SC sets the TP‑Reply‑Path parameter in the SM to be delivered. If the submitting SME is an MS, the reply path requesting procedure; in clause 4 of this annex may be applied. However, an SC may support the reply procedures without supporting the reply path requesting procedure; in that case, the SC sets the TP‑Reply‑Path parameter on another basis, which must be the case if the SM originates from an SME which is not an MS.