Abstract: The present invention relates to a transmitter and a receiver designed to improve the reliability of communications therebetween. During communication processes under UDP adopted as the transport layer, data having RTP headers is transmitted and received between the transmitter and the receiver. The receiver references the sequence numbers in the received RTP headers to verify the continuity of the numbers. If any data with a serially continuous sequence number is not received, the receiver finds that data to be missing and requests the transmitter to retransmit the data associated with the missing sequence number. The receiver then acquires the missing data that has been retransmitted. This invention applies to transmitters that transmit data and to receivers that receive the transmitted data.

Abstract: A musical instrument is disclosed which is capable of being operated in either of two different ways--through the use of a rotary record member, or through the manual manipulation of individual keys. The instrument disclosed includes a windchest used to supply air to either of two different principal valves, each of which is capable of being manipulated so as to set up resonance within an associated resonance chamber. Secondary valves are provided for varying the acoustically effective dimensions of the resonating chambers. All of the valves have actuators which extend into an area of the instrument capable of serving as a holder for the record member. When the record member is inserted in this holder and rotated cams on the record member engage the actuators so as to cause the production of a desired series of notes. Keys on the instrument are capable of being manually manipulated so as to cause the movement of levers into engagement with the actuators when no record member is present.