Do you know what an OLS and the DAS is? DAS is comprised of many different systems. The OLS is a stand alone system capable of performing no less than 11 different fuctions. I suggest you study the OLS-35 and what it is capable of. In addition to the OLS system the SU-35 also has other optical sensors/electronic warfare systems that does much of what the DAS does, such as detecting, identifying, and destroying hostile ground targets with a combination of radar warning receiver, OLS and anti radiation weapons.
Thank you for acknowledging that the OLS-35 is not the same system that is instaled on the T-50-2. However, i have to ask how you know the capability of the T-50's OLS system?
In addition, the Jane's artical stated that an OLS-35 sensor or an evolution of the OLS was mounted on the T-50 prototype, but in fact the first prototype had absolutely no OLS.