In one embodiment, there is disclosed a messaging system which allows a message originator to send a message to a message recipient, the message being presented to the recipient at a time selected by the message originator without any action being taken by the recipient. The dipoles are fed by a quadrature hybrid and impedance matching circuit. The transaction server receives order information from the remote terminals, matches a bid for an item to an offer for an item responsive to the bid corresponding with the offer, and communicates outstanding bid and offer information, and additional information back to the client terminals. Either one or both of an encoder that generates the signal and a decoder that decodes the signal may adaptively select a new rate control sequence based on operating conditions of the communication system, such as a change in signal to noise ratio.