The TT1 is a 1.54 m Alt-Az telescope designed and built by the Technology Working Group of the Astronomical Observatory of Capodimonte, Naples, Italy. The standardization process is of course one of the fundamental requirements for telescope control system design and development, well considered in the TT1 design. In this paper we present the approach used to identify a control system applicable to medium-size Alt-Az telescope. The TT1 control system architecture is based on a distributed working flow and it is PC-based, i.e. organized in several interconnected standard PCs and standard fast communication protocol. Every PC is based on the 'dedicated processing unit' concept and it makes real time own tasks independently by other units. Also, the extremely reduced communication flow between PCs, and the internal organization based on the preference given to software rather than hardware solutions, makes its control system extremely reliable, easily reconfigurable and upgradable, obsolescence deprived and independent from any hardware choice.