Abstract: The hydroacoustic system based on DOA estimation utilizes passive antenna composed of many hydrophones. The samples of the arriving acoustic signal must be gathered synchronously from each hydrophone. This enables to take advantage of parametric processing signals methods. These methods make possible determination of the amplitude and the phase relationship among particular hydrophones. The newest complex systems made up of many sub modules uses network solutions. In the case of Ethernet network some standards (e.g. Precision Time Protocol) are defined to enable synchronization of the data (samples) gathered from many hydrophones by the clock synchronization. When the antenna consists of few hydrophones then the special concentrator connected point-to-point to hydrophones can be utilized. This article discusses the issue related to PTP as well as concentrator based on FPGA technology, which uses simple UDP protocol. In the case of concentrator the synchronous method of the I/Q detection which not requires synchronous samples acquisition is also presented.