In the biomedical applications it is often necessary to collect measurement data from different devices. It is relatively easy, if the devices are equipped with a MIB or Ethernet interface, however often they feature only the asynchronous serial link, and sometimes the measured values are available only as the analog signals. The system presented in the paper is a low cost alternative to commercially available data acquisition systems. The hardware and software architecture of the system is fully open, so it is possible to customize it for particular needs. The presented system offers various possibilities to connect it to the computer based data processing unit - e.g. using the USB or Ethernet ports. Both interfaces allow also to use many such systems in parallel to increase amount of serial and analog inputs. The open source software used in the system makes possible to process the acquired data with standard tools like MATLAB, Scilab or Octave, or with a dedicated, user supplied application.