The present invention relates to a mobile telecommunications device such as a mobile telephone 1. The access point sends towards the stations periodic information arranged in time frames or beacon intervals. A restriction on the catcher line balances the fluid flow between the catcher and the additional vacuum channels. In a related embodiment, the audio characteristic that is varied is pitch of the selected portion. In an alternative embodiment, the control system also enables gated signal pass-through control while avoiding signal jamming.