Section: 5.3.5.1 Initiation of service level up- and downgrading
Content: The procedure is initiated by the mobile station in the "active" state of the call. It shall: - send a MODIFY message including the wanted value of the "maximum number of traffic channels" and/or the "wanted air interface user rate" parameters; - not change any of the other, possibly negotiated, parameters of the bearer capability information element; - start timer T323; and - enter the "mobile originating modify" state. Any internal resources necessary to support the next service parameters shall be reserved. If a dual service was negotiated at call setup, the mobile station shall initiate the service level up- or down-grading only during the data phase of the dual service. Upon receipt of the MODIFY message, the network shall check if the indicated maximum number of traffic channels can be supported and enter the "mobile originating modify" state.