Abstract: A method and apparatus for transmission of time critical data over a modem link is disclosed. Time critical data is intercepted by a modem at its host input-output port. The intercepted time critical data is injected directly at the top of the queue of data intended for transmission over the modem link. The injection of time critical data takes place at the input to the modulator in the form of specially identified frames, preferably of short duration. Time critical data is thus sent on a priority basis bypassing error correction circuits or routines, and bypassing data compression. At a receiving modem, time critical data is recognized in the demodulator as specially identified frames or packets. Such time critical data is recovered and immediately sent to the host without passing through the error correction process and without decompression.

Abstract: A fully digital phase aligner includes a control loop acting upon a delay line comprising at least a cascade of delay cells, each cell being individually configurable to produce one of two selectable propagation delays as a function of the logic state of a respective digital control signal. This is done by way of a shift register including a number of latches equal to the number of the cells of the delay line. An output tap of each latch of the shift register controls a respective delay cell of the delay line. A digital state machine in the control loop prevents any undesired oscillations.