Abstract: A MODEM can shorten the processing time of an interface disposed between a data terminal equipment (DTE) and the MODEM. The MODEM stores an object program of a procedure in a memory and switches an operational mode of the MODEM automatically corresponding to the prescribed procedure thereby executing the procedure corresponding to the current operational mode. The MODEM further comprises a timer which monitors the transits time between a completed procedure and the next procedure, and the MODEM starts the process of a specified operational mode based on a mode-setting-instruction of the procedure as well as monitoring the transitions time by using the timer, and executing a next specified operational mode when the timer times out, thereby allowing the MODEM to perform the various operational mode switches.

Abstract: A MODEM can shorten the processing time of an interface disposed between a data terminal equipment (DTE) and the MODEM. The MODEM stores an object program of a procedure in a memory and switches an operational mode of the MODEM automatically corresponding to the prescribed procedure thereby executing the procedure corresponding to the current operational mode. The MODEM further comprises a timer which monitors the transits time between a completed procedure and the next procedure, and the MODEM starts the process of a specified operational mode based on a mode-setting-instruction of the procedure as well as monitoring the transitions time by using the timer, and executing a next specified operational mode when the timer times out, thereby allowing the MODEM to perform the various operational mode switches.

Abstract: An encoding (or decoding) method, by which raw data of 1 line is converted into, for example, modified Huffman (MH) code (or MH code is converted into raw data) by obtaining a cumulative run-length code every transition point, at which there occurs a transition or change between a run of white pixels to another contiguous run of black pixels, from the beginning of the line and then converting the cumulative run-length code to the MH code (or converting the MH code to the cumulative run-length code). The cumulative run-length code is defined by both of data, which indicates that a pixel of a run just prior to the transition point is black or white, and data representing a cumulative run-length of the run up to the pixel thereof just prior to the transition point. Thus, an encoding or decoding processing can be performed at a high speed.

Abstract: A data processing apparatus consists of an input buffer for storing one or more pieces of line data which each are formed of pieces of picture data and adding a specific code to each of the line data, a searching section for searching the input buffer for one or more specific codes, a search control section for (1) calculating a number Dx of pieces of picture data stored in the input buffer, (2) instructing the searching section to search the input buffer for one or more specific codes when the number Dx reaches a reference number, (3) repeatedly adding an incremental value to the reference number to increase the reference number in cases where no specific code is found out by the searching section, and (4) repeatedly instructing the searching section to search the input buffer for one or more specific codes when the number Dx reaches the reference number increased until at least one specific code is found out by the searching section, a data taking out section for taking out one or more pieces of line data s

Abstract: A Viterbi decoding method, in which consecutive input data bits Q.sub.6n .about.Q.sub.1n are first converted into consecutive code bits Q.sub.6n .about.Q.sub.3n Y.sub.2n Y.sub.1n Y.sub.0n at a time instant n by use of a Trellis encoder. Then, a branch metric, which is a minimum Euclidean distance between a reception signal point and each of signal points (namely, Trellis codes Q.sub.6 .about.Q.sub.3 Y.sub.2 Y.sub.1 Y.sub.0) in a signal space diagram, corresponding to each of eight states 0 to 7 and a corresponding signal point are obtained. Further, a sum of the branch metric corresponding to each state and a corresponding path metric at a time instant (n-1), which is a sum of corresponding branch metrics since a time instant 1 to the time instant (n-1) is calculated. Then, the path metric corresponding to each state is updated by replacing it with the calculated sum of the corresponding branch metric and the corresponding path metric obtained at the time instant (n-1).