A more than 25 year old laser interferometer has been further developed in order to handle the signals also by computers. A TTL signal converter has been built in using an analog comparator unit type LM319. A National Instruments 6341 OEM measurement card was implemented too. The modernized laser interferometer has been verified with a precise Renishaw XL-80 interferometer. A vibrometer unit has been also calibrated with the updated interferometer.