A memory system using a simultaneous bi-directional input/output (SBD I/O) circuit on an address bus line. The memory system includes a first address I/O circuit and a second address I/O circuit, which are connected by the address bus line. The first address I/O circuit may be included in a controller, transmits an address signal to the address bus line, and receives an acknowledgement signal from the address bus line. The second address I/O circuit may be included in a memory device (such as dynamic random access memory (DRAM)), transmits the acknowledgement signal to the address bus line, and receives the address signal from the address bus line. The memory system may also include an error correction circuit unit which generates the acknowledgement signal indicating if an error is present in the address signal received by the second address I/O circuit.