- What the 14 Competencies Actually Are
- Exam Format and Test-Day Mechanics
- Hardware Core: Domains 1 Through 9
- Networking and Portables: Domains 10 and 11
- Troubleshooting, Maintenance, and Security: Domain 12
- Operating Systems and File Management: Domains 13 and 14
- Sequencing the 14 Domains in Your Prep
- What Happens After You Pass
- Frequently Asked Questions
- The ETA International CST exam covers 14 unweighted competencies, so no single domain can be safely skipped.
- You answer 80 questions in two hours and need 75% to pass; the exam is theory-only.
- The competency list names legacy and current technologies, so expect older hardware alongside Windows 11, Linux, and macOS.
- The exam fee is USD 80; remote proctoring through ExamRoom.AI adds USD 16, even on a free retake.
What the 14 Competencies Actually Are
The Computer Service Technician (CST) certification from ETA International is built on a published document titled Computer Service Technician - CST Competency Requirements (copyright 2025). That document lists 14 headings, and those headings are the exam's content areas. Unlike some certification blueprints, ETA does not publish percentage weights for each heading. The competencies are presented as an unweighted list.
That detail matters for how you plan. With no published weights, you cannot decide that one domain is "only 5% of the exam" and skip it. Every heading is fair game, and the practical response is to build at least working competence across all 14. If you are new to the credential itself, the overview in What Is CST Certification? explains where it fits, and CST Requirements 2026: Eligibility, Prerequisites & How to Qualify covers who can sit for it.
Exam Format and Test-Day Mechanics
Before diving into the domains, it helps to know what you are preparing for. The CST is a proctored theory examination. There is no hands-on assessment, so nobody will ask you to swap a DIMM or crimp a cable. You demonstrate knowledge through 80 questions answered within two hours, and the passing score is 75%. For a deeper look at the cut score, see CST Passing Score 2026: Exactly What You Need to Pass.
| Item | CST Detail |
|---|---|
| Issuing body | ETA International |
| Questions / time | 80 questions in two hours |
| Passing score | 75% |
| Exam fee | USD 80 |
| Remote proctoring add-on | USD 16 two-hour fee through ExamRoom.AI, arranged via ETA |
| Onsite delivery | ETA Certification Administrator; Trapeza online testing or paper/pencil |
| Retake | One free retake within one year of the initial session |
| Certification term | Four years |
Test-day rules that affect your preparation
- Photo ID is required. Bring valid identification to either an onsite or remote session.
- Scratch paper is permitted, and so is a non-programmable scientific calculator. Used scratch paper must be surrendered at the end.
- The calculator is a hint. Several domains involve arithmetic: power supply wattage, voltage and current relationships, storage capacity, and network addressing. Practice with a basic scientific calculator so you are not fumbling on exam day.
- Remote testing costs extra. The USD 16 ExamRoom.AI proctoring fee applies even when you are using your free retake, so budget for it. Our CST Certification Cost 2026: Complete Pricing Breakdown lays out the full picture.
Scheduling specifics are covered in CST Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Hardware Core: Domains 1 Through 9
Nine of the 14 headings deal with the physical machine. Together they describe the daily work of a bench or field technician: handle components safely, assemble a system, understand what the board, processor, memory, storage, cards, ports, and power supply each contribute, and know how they interact.
Domain 1: Safety Procedures / Handling / Environmental Awareness
This is the foundation, and it is easy to underestimate because it feels like common sense. Expect questions about protecting equipment and people.
- Electrostatic discharge (ESD) precautions and proper handling of sensitive components
- Personal safety around power supplies, monitors, and other hazardous equipment
- Environmental awareness, including appropriate handling and disposal of components
Domain 2: Computer Assembly and Disassembly
Even though there is no hands-on test, you must know the correct order and method for building and tearing down a system.
- Component installation and removal sequences
- Connector identification, orientation, and seating
- Recognizing compatibility between parts before you assemble them
Domain 3: Motherboards / Mainboard and Buses / System Resources
The board is the hub that everything else plugs into, so this domain tends to connect to nearly every other one.
- Board form factors, chipsets, and expansion slot types
- Bus architectures, including older and current standards
- System resources such as interrupts, DMA channels, and I/O addressing
Domain 4: Processor Characteristics
Know what distinguishes one CPU from another and how a processor must match its socket and board.
- Clock speed, cache, and core concepts
- Sockets, packaging, and cooling requirements
- How processor choice constrains motherboard and memory choice
Domain 5: Additional Memory Characteristics
The competency heading says "additional" memory, which points toward detail beyond the basics of RAM versus storage.
- Memory module types, speeds, and form factors
- Capacity, compatibility, and installation considerations
- Cache and other memory roles within the system
Domain 6: Secondary Storage Devices
Storage questions range from legacy media to modern drives, which fits ETA's practice of naming both.
- Hard drive and solid-state drive operation and interfaces
- Optical and removable media
- Drive configuration, capacity calculations, and the idea of redundancy
Domain 7: Adapter Cards and Peripheral Devices
- Video, sound, network, and other expansion cards
- Matching a card to the correct slot and bus
- Peripheral installation, drivers, and basic configuration
Domain 8: Input/Output (I/O) Ports
- Port and connector identification, both legacy and current
- Typical device-to-port pairings and cable types
- Basic speed and capability differences between interfaces
Domain 9: Power Concepts and Power Supplies
This is where the calculator earns its place. Power questions often involve relationships between voltage, current, and wattage.
- Power supply types, connectors, and output voltages
- Basic electrical concepts behind computer power
- Protective devices and clean-power considerations
Key Takeaway
Do not study Domains 3 through 9 as isolated lists. Questions often hinge on how components relate, such as whether a card fits a bus, a processor suits a board, or a supply can feed a load. Build comparison charts rather than flashcards of single facts.
Networking and Portables: Domains 10 and 11
Domain 10: Basic Networking Concepts Applicable to Computer Service
Note the phrasing: this is networking as it applies to a service technician, not a network engineer. The scope is foundational.
- Common network types, topologies, and media
- Network interface hardware and basic connectivity
- Core addressing and protocol ideas a technician encounters when connecting a computer
Domain 11: Portables
Laptops and other portable systems differ from desktops in ways that generate their own question set.
- Portable-specific components, including batteries and power management
- Differences in upgrading and servicing compact systems
- Wireless connectivity and docking or expansion options
If your background is entirely in desktop repair, give Portables deliberate attention. It is a distinct heading, and it will not be covered by your desktop knowledge alone. If your electronics background is thin, ETA's competency document suggests CETa or equivalent basic electronics preparation, though standalone CST does not require CETa. That suggestion is especially relevant to the power and portables material.
Troubleshooting, Maintenance, and Security: Domain 12
Domain 12: Troubleshooting / Preventive Maintenance / Security Measures
This heading bundles three skills into one, and it is where scenario-style questions are most likely to pull knowledge from every other domain.
- A logical troubleshooting method: identify the symptom, isolate the cause, apply a fix, and verify
- Preventive maintenance routines for hardware and software
- Security measures that a technician implements or recommends
Because a symptom could trace back to power, memory, storage, a port, or the operating system, this domain rewards candidates who understand the whole machine. Work through it last in your hardware review, after you have the component domains in place. Candidates wondering how demanding the exam feels overall can read How Hard Is the CST Exam? Complete Difficulty Guide 2026.
Operating Systems and File Management: Domains 13 and 14
Domain 13: Operating Systems (Windows™ 7, 8, 10, 11 / Linux / Apple mac™)
The competency heading itself names the versions: Windows 7, 8, 10, and 11, plus Linux and Apple macOS. That is a notably broad list, and the inclusion of older Windows releases alongside Windows 11 reflects the legacy-plus-current approach.
- Installation, configuration, and basic administration across the named systems
- Differences in interface, tools, and terminology between Windows, Linux, and macOS
- Version-specific features that distinguish Windows 7, 8, 10, and 11
Domain 14: File Management
- File systems, directory structures, and file attributes
- Organizing, copying, moving, and protecting files
- Backup and recovery concepts at the file level
Sequencing the 14 Domains in Your Prep
Since the domains are unweighted, the smartest use of generic study technique is simply to order your reading so that each topic builds on the last. Here is one sequence that follows the dependencies between headings. Pair it with the broader plan in CST Study Guide 2026: How to Pass on Your First Attempt.
Foundations
- Domain 1 (safety and ESD) and Domain 2 (assembly and disassembly)
- Domain 9 (power), because every later component depends on it
The Platform
- Domains 3 and 4 (motherboard, buses, resources, processor)
- Domain 5 (memory)
Connections
- Domains 6, 7, and 8 (storage, cards and peripherals, I/O ports)
- Domain 11 (portables) while hardware concepts are fresh
Software and Synthesis
- Domains 13 and 14 (operating systems, file management) and Domain 10 (networking)
- Domain 12 last, using it to tie everything together with scenarios
Finish with timed practice. The exam gives you two hours for 80 questions, which is a comfortable pace of well over a minute per item, so the challenge is breadth rather than speed. Use the CST practice tests to find which domains still trip you up, then return to the relevant section above. When you want a compact refresher before test day, the CST Cheat Sheet 2026: One-Page Review of Must-Know Facts is a useful companion.
What Happens After You Pass
Passing gives you four years of certification. To maintain it, you submit the maintenance form, complete 10 continuing-education contact hours per year (40 over the four-year cycle) or provide supervisor-completed employer verification, and pay USD 25 per year (USD 100 per four-year cycle).
There are a few related pathways worth knowing about:
- Free retake: One free examination retake is available within one year of your initial session, which lowers the stakes of a first attempt.
- A+ rollover: A valid CompTIA A+ (ce), but not lifetime A+, qualifies for a separate USD 80 CST rollover route.
- Journeyman path: This requires CETa and at least two years of combined training and experience.
For the career side, CST Jobs describes the roles that value this credential, CST Salary Guide 2026: Complete Earnings Analysis looks at earnings, and Is the CST Certification Worth It? Complete ROI Analysis 2026 weighs the investment. If you want structured preparation, see CST Training.
Key Takeaway
The CST rewards broad, connected knowledge of the whole computer, from ESD precautions to Linux file structures. Cover all 14 headings, practice with a calculator, and use your free retake as a safety net rather than a plan.
Frequently Asked Questions
No. The 14 headings come from ETA International's competency requirements document and are presented as unweighted competencies. Plan to be competent in all of them rather than concentrating on a few.
No. It is a proctored theory examination of 80 questions in two hours, with a 75% passing score. You will need to understand assembly and troubleshooting procedures, but you will not perform them physically during the exam.
A non-programmable scientific calculator is permitted, along with scratch paper. Used scratch paper must be surrendered at the end of the session, and photo ID is required.
Domain 13 names Windows 7, 8, 10, and 11, along with Linux and Apple macOS. Candidates should be prepared for both older and current Windows versions as well as the two non-Windows platforms.
ETA offers one free examination retake within one year of your initial session. If you test through remote proctoring, the USD 16 ExamRoom.AI fee still applies to the retake. Review the domains where you were weakest before scheduling it, and see CST Pass Rate 2026: What the Data Shows for context on what to expect.