D.8 Replying possibilities for Phase 1 mobile stations
23.0403GPPRelease 17Technical realization of the Short Message Service (SMS)TS
The Phase 2 mobile stations should support the procedures in this annex (if they fulfil the criteria in clause 2 of it). Yet, Phase 1 mobile stations, too, may apply steps (1) and (2a) in clause 6 of this annex, i.e. reply via the original SC, automatically or manually (by choosing selected SC = original SC), despite the fact that the TP‑Reply‑Path parameter shall be ignored by them. The delivery of the reply MO SM cannot be guarantied in this case, yet the possibility of delivery may be improved (especially if the originating SME is not an MS).