What are the specific roles of an installations technician?

Specific role of installation technician could be elaborated as follows:

• Making the site ready for installation of particular equipment.
• Opening the equipment box from the wooden crate and to ensure that all accessories are present inside
• Installing the equipment and make it operational
• Test run for specified time and fine tuning.
• Training of  the operator 
• Formal handover note signed by the accepting Manager
•  

We have technicians in different field of engineering, so be specific on your question, Installing CCTV,  Telecommunication network, Electronics, Refrigerator/AC technicians, Auto Technicians and the rest