A telecommunications device is operable to perform in-call handoff between a cellular network and a packet-switched network. The telecommunications device includes interfaces connecting the telecommunications device with a circuit-switched network and a packet-switched network. The telecommunications device is operable to receive a request from a multi-mode device to handoff an existing call over a cellular network to the packet-switched network. The existing call is between the multi-mode device and a remote party and was established without the telecommunications device. In response to receiving the request, the telecommunications device establishes a first call leg in the packet-switched network with the multi-mode device. The multi-mode device sends a transfer signal to a call server in the cellular network requesting the transfer of the on-going voice session from itself to the telecommunication device. A second call leg is setup between the telecommunication device and a remote party. The telecommunication device helps to bridge the first call and second call leg, and then the multi-mode device can continue the voice session in packet switched network.