Final answer:
The three-character code is known as a Special Experience Identifier (SEI), used to denote specialized skills or training in the personnel data system.
Step-by-step explanation:
The three-character code that identifies special experience and training not otherwise identified in the personnel data system is commonly referred to as a Special Experience Identifier (SEI). SEIs are used in various organizations, including the military and certain professional fields, to denote specialized skills, training, or experiences that personnel have acquired beyond their standard job classification.
These codes are critical for workforce planning and management, as they help in detailing qualifications and capabilities that are not apparent through basic job titles or codes.
The three-character code that identifies special experience and training not otherwise identified in the personnel data system is known as a MOS code or Military Occupational Specialty code. These codes are used by the military to categorize the skills and expertise of service members.