In this node the call is placed fromt he Agent's phone once the Agent accepts, so there will not be any zip tone as the call is been place fromt he agent's extension.
In this mode only 1 port is allocated and that is for the Reservation call. And from 7.5.6 all the reservation calls are dummy calls and does not go through the CallManager. Hence no Zip Tone for the reservation call.
For all other modes you can still get one zip tone when the customer call is transferred by the dialer to the agent. Prior to 7.5.6 there would have been 2 zip tones. One for reservation call and one when the customer call is transferred to the agent.