Explanation/Reference:
Explanation:
Apple Service Toolkit includes:*
AudioTest - plays a series of tones through each speaker and listens for those same tones via the

microphone.
Diagnostic Gateway (DG) - software that runs on a dedicated Intel-based Mac using Mac OS X Server

10.6/10.7 and serves up tools to triage computers via NetBoot, recording test results as log files.
Mac Resource Inspector (MRI) - triage tool that provides a fast check of internal hardware

components for all Intel- based computer systems.
Notebook Adapter Diagnostic (NAD) - triage tool that reports on the condition of Intel-based notebook

power adapters.
Cooling System Diagnostic (CSD) - evaluates the thermal sensors, fans and heat sink in MacBook Pro

(Early 2011) models and will either confirm correct operation or help diagnose a service issue.
Gateway Manager - software application used to remotely configure and manage the Diagnostic

Gateway server as well as access logs created by diagnostic tools.
Test Patterns Tool (TPT) - identifies pixel anomalies in LCD panels in Apple Display, iMac, MacBook,

MacBook Pro, and MacBook Air systems.
Server Bit Setter (SBS) - Repair tool used after replacing logic boards in late model Mac mini Servers

or backplane boards in late model Mac Pro Servers.
Video System Test (VST) - is used to test video issues in specific MacBook Pro models.

Blank Board Serializer (BBS) - Allows technicians to set the system serial number on replacement

Main Logic Board (MLB) service parts.
AST Keyboard (OS) - service tool for in-depth testing of keyboards.

AST Trackpad (OS) - service tool for in-depth testing of trackpads.

Storage Diagnostic (OS) - Repair tool for testing HDD or SSD modules.

Image Persistence Test (EFI) - triage tool for identifying image persistence anomalies on IPS displays