A user equipment, UE, for a voice call service in a communication system, wherein: the UE is configured to communicate with a communication network to determine if the communication network is capable of servicing a voice call in a packet-switched, PS, domain or not, and to service the voice call with the communication network in the PS domain if the communication network is capable of servicing the voice call in the PS domain, wherein the PS domain is an Internet Protocol, IP, Multimedia Subsystem, IMS, domain; and wherein the UE is configured to use a specific tag in an IMS Centralized Services, ICS, registration for indicating support for an alternative voice delivery mechanism and for notifying a relevant domain selection application server of the IMS domain of the UE selection of an alternative voice delivery mechanism in order to adapt a Terminating Access Domain Selection, T-ADS, in response to a ICS-capable UE not being configured to support UE-assisted T-ADS or in response to an operator's policy configured not to allow the use of UE-assisted T-ADS; wherein the UE is configured to communicate with the communication network to determine if the communication network is configured to use a Voice over IP, VoIP, of the IMS domain or not; wherein the UE is configured to determine whether an operator policy of the communication network allows at least one alternative voice delivery mechanism or not, if the communication network is not configured to use the VolP of the IMS domain; wherein the UE is configured to service the voice call with the communication network using the at least one alternative voice delivery mechanism if the operator policy of the communication network allows the at least one alternative voice delivery mechanism; wherein the at least one alternative voice delivery mechanism includes at least one of a circuit-switched, CS, fallback mechanism and a VolP with CS over enhanced packet system, EPS, mechanism; and wherein the VolP with CS over EPS mechanism comprises a mechanism where voice frames are delivered using the IMS domain and CS signaling is encapsulated in IP. the UE is configured to communicate with a communication network to determine if the communication network is capable of servicing a voice call in a packet-switched, PS, domain or not, and to service the voice call with the communication network in the PS domain if the communication network is capable of servicing the voice call in the PS domain, wherein the PS domain is an Internet Protocol, IP, Multimedia Subsystem, IMS, domain; and wherein the UE is configured to use a specific tag in an IMS Centralized Services, ICS, registration for indicating support for an alternative voice delivery mechanism and for notifying a relevant domain selection application server of the IMS domain of the UE selection of an alternative voice delivery mechanism in order to adapt a Terminating Access Domain Selection, T-ADS, in response to a ICS-capable UE not being configured to support UE-assisted T-ADS or in response to an operator's policy configured not to allow the use of UE-assisted T-ADS; wherein the UE is configured to communicate with the communication network to determine if the communication network is configured to use a Voice over IP, VoIP, of the IMS domain or not; wherein the UE is configured to determine whether an operator policy of the communication network allows at least one alternative voice delivery mechanism or not, if the communication network is not configured to use the VolP of the IMS domain; wherein the UE is configured to service the voice call with the communication network using the at least one alternative voice delivery mechanism if the operator policy of the communication network allows the at least one alternative voice delivery mechanism; wherein the at least one alternative voice delivery mechanism includes at least one of a circuit-switched, CS, fallback mechanism and a VolP with CS over enhanced packet system, EPS, mechanism; and wherein the VolP with CS over EPS mechanism comprises a mechanism where voice frames are delivered using the IMS domain and CS signaling is encapsulated in IP.