| CPC H04M 3/42136 (2013.01) [H04M 3/02 (2013.01); H04L 65/1104 (2022.05)] | 17 Claims | 

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               1. A method performed by a processor of a wireless device for signaling a network regarding customized ringing signal (CRS) capability, comprising: 
            receiving from the network a first INVITE message notifying the wireless device of a first incoming call; 
                determining the first INVITE message indicates that the network provides a first CRS service and the wireless device supports a CRS function; 
                including an indication in a response to the first INVITE message that the wireless device supports the CRS function in response to determining that the first INVITE message includes an alert information header field indicating that the network provides the first CRS service; 
                receiving from the network a second INVITE message notifying the wireless device of a second incoming call; 
                determining the second INVITE message indicates that the network does not provide the second CRS service; and 
                providing a response to the second INVITE message without the alert information header field to initiate a default ring. 
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