Simple, inexpensive, general-purpose devices and methods achieve simultaneous, full-duplex and bi-directional communication of analog, digital or audio signals across a single conductor. "Sifudu" transceivers, which stands for "simultaneous and full-duplex," reduce the number of cables necessary for transferring information between two or more terminals at a given rate, and/or facilitate information transfer at a higher rate than traditional circuits across the same number of cables. The transceivers can accommodate both digital and analog signals of arbitrary polarity. Since a sifudu circuit is capable of transmitting analog signals, it is also capable of transmitting digital signals in frequency, phase, or amplitude shift keyed form, thus opening the possibility of realizing higher baud rate than other simultaneous bidirectional communication systems that transfer digital data only, one bit at a time in each direction. The transceivers can be connected into a multi-terminal network configurations including chain, star, tree, woods topologies, alone or in combination.