Final answer:
Typically, working on a PBX system requires understanding telecommunications infrastructure and may involve some familiarity with network security, but not knowledge of programming languages or expertise in social sciences.
Step-by-step explanation:
When working on a voice installation with a private branch exchange (PBX) system, it is typically required to have a understanding of telecommunications infrastructure.
This involves knowing how to configure and troubleshoot the hardware and software that comprise the PBX system, which includes phones, servers, and networking equipment. Unlike working with social systems or large bureaucracies, PBX installations do not typically require expertise in social sciences, nor do they necessarily require a knowledge of programming languages, except sometimes for advanced customization.
Familiarity with network security is also often important, as securing voice communications is critical to protect against eavesdropping and unauthorized access.