3GPP 24.501 v20.0.0 — the document's own text

5.2.2.3.7 eCALL-INACTIVE

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The UE camps on a suitable cell or an acceptable cell in a PLMN selected as specified in 3GPP TS 23.122 [5] but initiates no 5GMM signalling with the network and ignores any paging requests.

The UE shall leave substate 5GMM-DEREGISTERED.eCALL-INACTIVE state only when one of the following events occur:

if the USIM is removed, the UE enters substate 5GMM-DEREGISTERED.NO-SUPI;
if coverage is lost, the UE enters substate 5GMM-DEREGISTERED.PLMN-SEARCH;
if the UE is deactivated (e.g. powered off) by the user, the UE enters state 5GMM-NULL;
if the UE receives a request from upper layers to establish an eCall over IMS or an IMS emergency session according to clause H.6 in 3GPP TS 23.167 [6], the UE enters state 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION. The UE then uses the relevant 5GMM and 5GSM procedures to establish the eCall over IMS or an IMS emergency session according to clause H.6 in 3GPP TS 23.167 [6] at the earliest opportunity; or
if the UE receives a request from upper layers to establish a call to an HPLMN designated non-emergency MSISDN or URI for test or terminal reconfiguration service, the UE enters state 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION. Once the registration procedure is completed, the UE uses the relevant 5GMM and 5GSM procedures to establish the non-emergency call.