This document provides common definitions and guidelines on system architectures and security controls for remote functions such as remote operation, remote monitoring, remote engineering and remote maintenance of Industrial Control and Automation Systems (IACS), Basic Process Control Systems (BPCS), Safety Instrumented Systems (SIS), package control systems, and monitoring-only systems. The objective of the document is to highlight specific risks and challenges related to remote function, provides high-level view of system and security architectural consideration and presents reference system architectures used to implement remote function for typical use cases.