abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a research has been performed to determine the prominent supplier of the equipments of bss systems in tci company. since, up to now, the conservative approaches of decision making have been just done in this area, therefore, we intended to use the scientific decision making methods for the first time. the reasons are clear. obviously, the conservative methods cause faults in the selection proves and subsequently, they will cause tci company to sustain future costs. in contrast, using scientific decision making methods, all effective criteria are determined and the prominent vendor is then selected based on scientific approaches without the interference of humans in all steps. moreover, to emphasize the capabilities of this project, all the famous methods of madm such as electre, topsis and ahp are used. it is noted that the first two of the mentioned methods (i.e. electre and topsis) are coded in matlab software for the first time and are then exerted on the 80 arrays-decision making matrix. the comparison among the results of these codes and ones elicited from expert choice 11 software (which uses ahp method) shows the validity of these codes.