A first mobile phone in a video call with a second mobile phone, the first mobile phone comprising: a transceiver configured to: receive (1004, 1102), from the second mobile phone, a request for device list information of a home network of the first mobile phone; discover (1005-1006, 1103, 1104) one or more electronic devices in the home network by using an M-SEARCH message, the one or more electronic devices including a first electronic video telephony device; transmit (1007, 1105) the device list information to the second mobile phone; receive (1011, 1109) a message including a telephony identity of a second electronic video telephony device from the second mobile phone; select the first electronic video telephony device to receive a call according to a user's request and transmit (1013, 1111) an Enhanced Initiate Call message to the first electronic video telephony device including the telephony identity of the second electronic video telephony device, for establishing a call session between the first electronic video telephony device and the second electronic video telephony device; receive (1014, 1112), from the first electronic video telephony device, a response for initiating a video call between the first electronic video telephony device and the second electronic video telephony device; and transmit (1015, 1113), to the second mobile phone, the response for initiating the video call between the first electronic video telephony device and the second electronic video telephony device, wherein an existing call between the first mobile phone and the second mobile phone is modified (1016, 1114) from a video call to a voice call; wherein the Enhanced Initiate Call message includes the telephony identity of the second electronic video telephony device and a call type specifying an HD video call; and wherein the call type indicates a type, an audio quality and a video quality of a call to be generated for the call session. a transceiver configured to: receive (1004, 1102), from the second mobile phone, a request for device list information of a home network of the first mobile phone; discover (1005-1006, 1103, 1104) one or more electronic devices in the home network by using an M-SEARCH message, the one or more electronic devices including a first electronic video telephony device; transmit (1007, 1105) the device list information to the second mobile phone; receive (1011, 1109) a message including a telephony identity of a second electronic video telephony device from the second mobile phone; select the first electronic video telephony device to receive a call according to a user's request and transmit (1013, 1111) an Enhanced Initiate Call message to the first electronic video telephony device including the telephony identity of the second electronic video telephony device, for establishing a call session between the first electronic video telephony device and the second electronic video telephony device; receive (1014, 1112), from the first electronic video telephony device, a response for initiating a video call between the first electronic video telephony device and the second electronic video telephony device; and transmit (1015, 1113), to the second mobile phone, the response for initiating the video call between the first electronic video telephony device and the second electronic video telephony device, wherein an existing call between the first mobile phone and the second mobile phone is modified (1016, 1114) from a video call to a voice call; receive (1004, 1102), from the second mobile phone, a request for device list information of a home network of the first mobile phone; discover (1005-1006, 1103, 1104) one or more electronic devices in the home network by using an M-SEARCH message, the one or more electronic devices including a first electronic video telephony device; transmit (1007, 1105) the device list information to the second mobile phone; receive (1011, 1109) a message including a telephony identity of a second electronic video telephony device from the second mobile phone; select the first electronic video telephony device to receive a call according to a user's request and transmit (1013, 1111) an Enhanced Initiate Call message to the first electronic video telephony device including the telephony identity of the second electronic video telephony device, for establishing a call session between the first electronic video telephony device and the second electronic video telephony device; receive (1014, 1112), from the first electronic video telephony device, a response for initiating a video call between the first electronic video telephony device and the second electronic video telephony device; and transmit (1015, 1113), to the second mobile phone, the response for initiating the video call between the first electronic video telephony device and the second electronic video telephony device, wherein an existing call between the first mobile phone and the second mobile phone is modified (1016, 1114) from a video call to a voice call; wherein the Enhanced Initiate Call message includes the telephony identity of the second electronic video telephony device and a call type specifying an HD video call; and wherein the call type indicates a type, an audio quality and a video quality of a call to be generated for the call session.