Abstract: An error detection system for a discrete receiver. Sequences of bits together forming frames of information comprise the signal received by the discrete receiver. The signal is decoded by a convolutional decoder and is re-encoded by an encoder. Successive portions of nonoverlapping sets of adjacently positioned bits of the re-encoded signal formed by the encoder are compared with corresponding bits of a signal representative of the signal received by the receiver. When excessive numbers of the successive portions of the signals which are compared include bit dissimilarities, a bad frame indication is generated.

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.