Abstract: Data transfer apparatus (211,213) for a radiotelephone peripheral using a time multiplexed data bus for communication with a bus master of the radiotelephone couples peripheral devices external to the radiotelephone and other user information inputting devices, such as a handset for a cellular mobile radiotelephone, to the radiotelephone's central processor and speech processor. The data transfer apparatus generates time slots in frame formats in which the information is sent over the data bus. The entire message, information bits and the header, sent in a time slot from a peripheral device to the bus master is used to determine bus contention. Bus contention resolution during the start-up of data bus operation sets the priority with respect to other data transfer apparati with which a peripheral device's data transfer apparatus is able to access the bus during normal operation.

Abstract: A radiotelephone data transfer apparatus connects peripheral devices external to the radiotelephone and other user information inputting devices, such as a handset for a cellular mobile radiotelephone, to the radiotelephone's central processor and speech processor. The data bus apparatus generates frame formats in which the information is sent over the data bus. The frame formats are further subdivided into time slots, the time intervals in which individual messages are sent. The data transfer apparatus is configured so that messages sent to the cellular radiotelephone's speech processor are not flow controlled, while messages sent to the radiotelephone's central processor are flow controlled. Further, the radiotelephone's central processor controls operation of peripheral devices attached to the radiotelephone.