[Nexus 4 General] bsbachert:
I've been looking into this for our nexus 4, and here is what I am trying.

Tmobile wifi calling now uses IMS, so I downloaded this,

http://code.google.com/p/the-ims-open-source-project-for-android/downloads/list

then entered all this data into the app.

<string name="def_proxy_host">sba.sipgeo.t-mobile.com</string>

<string name="def_proxy_port">5061</string>

<string name="def_registrar_host">msg.pc.t-mobile.com</string>

<string name="def_registrar_port">5061</string>

<string name="def_registrar_expire_time">3600</string>

<string name="def_registrar_user_name_schema">sip</string>

<string name="def_registrar_user_name">12066311973</string>

<string name="def_registrar_user_name_domain">msg.pc.t-mobile.com</string>

<string name="def_preferred_identity">sip:12066311973@msg.pc.t-mobile.com</string>

<string name="def_auth_user_name_prefix" />

<string name="def_auth_user_name_info">12066311973</string>

<string name="def_auth_user_name_domain">msg.pc.t-mobile.com</string>

<string name="def_auth_user_password">TMO-VOIP-TRIAL</string>

<string name="def_auth_type">Aka</string>

<string name="def_auth_simulteneous">false</string>

<string name="def_auth_forces">UAS</string>

<string name="def_local_port">5061</string>

<string name="def_user_agent">T-mobile TAS</string>

<string name="def_realm">msg.pc.t-mobile.com</string>

<string name="def_global_ip_discovery">false</string>

<string name="def_dns_lookup">true</string>

<string name="def_connection_type">TLS</string>

<string name="def_max_forwards">70</string>

<string name="def_use_rport">false</string>

<string name="def_required_100rel">false</string>

<string name="def_supported_100rel">true</string>

<string name="def_supported_eventlist">true</string>

<string name="def_use_resource_reservation">true</string>

<string name="def_supported_path">false</string>

<string name="def_xdm_xcap_root">https://apxdm.sipgeo.t-mobile.com:443/ap</string>

<string name="def_xdm_xui_name">sip:reguser@msg.pc.t-mobile.com</string>

<string name="def_xdm_xui_password" />

<string name="def_xdm_auth_name" />

<string name="def_xdm_password" />

<string name="def_xdm_send_full_document">true</string>

<string name="def_msrp_chunk_size">4096</string>

<string name="def_msrp_local_port">8509</string>

<string name="def_use_simul_connection">false</string>

<string name="def_use_sigcomp">false</string>

<string name="def_use_debug_log">false</string>

<string name="def_use_invite_refresh">false</string>

<string name="def_refresher">UAC</string>

<string name="def_session_expires_time">3600</string>

<string name="def_min_session_expires_time">600</string>

<string name="def_force_srtp">true</string>

<string name="def_dtmf_payload_type">inband</string>

<string name="def_use_feature_tags">true</string>

<string name="hello">Hello World!</string>

<string name="app_name">IMS Service</string>

Tried to start the app, came back as invalid sim card. I then tried to find a micro TM9177, whice is the type needed for wifi calling, well, they dont make one. Talked to a rep at tmobile, and he suggested buying the regular TM9177 sim card, and triming it to fit the micro sim card slot, so I ordered one, will be here tomorrow. Before he hung up, he told me to make sure to turn IMS on before I try it. Do so by typing *#*#4636#*#* on your phone keypad and a menu pops up, you can turn on IMS, and SMS over IMS there. He said all this may work, but he was not sure. He thinks you would have to shut your phone signal completly off for this to work, since it is app based and not in the framework.( airplane mode?) I'll let you know if it does.

Crossing my fingers.