When a key is in the normal position an electrical talk path connects the front and rear cords. A telephone switchboard is a device used to connect circuits of telephones to establish telephone calls between users or other switchboards. However, for the wide variety of installations and ranges of power ratings, there are local work practices, regulations and of course international standards. There. The purpose of this manual is to assist the user in developing safe and eficient procedures for the installation, maintenance and operation of the equipment. For additional information, refer to NEMA Standards Publication PB2. 1 “General Instructions for Proper Handling, Installation, Operation, and. Learn how to wire a complete switchboard with 2 switches and a 5-pin socket in this step-by-step tutorial. This video covers switchboard internal wiring, soc.