Patent ID: 9426250
Filing Date: 2016-08-23
CPC Classification: H04L

Claim Text:
1. A method comprising: sending, by a first terminal, capability information of the first terminal to a second terminal, wherein the sending occurs without, or prior to, a circuit-switched call conducted between the first terminal and the second terminal; receiving, at the first terminal, capability information of the second terminal; establishing the circuit-switched call between the first terminal and the second terminal; and initiating, by the first terminal, a service change during the circuit-switched call conducted between the first terminal and the second terminal, wherein the first terminal initiates the service change by at least sending, to the second terminal, a service change request using a session initiation protocol during the circuit-switched call, wherein the capability information of the first terminal and the second terminal comprises multimedia call related parameters and an indication that a visited network supports a service change between a speech only call and a multimedia call.