What is CoaXPress?

Glossary
CoaXPress

CoaXPress is a high-speed digital interface standard for machine vision cameras that transmits video, control data, triggers, and power over a single coaxial cable. Developed by the Japan Industrial Imaging Association (JIIA) and standardized internationally as part of the GenICam family, CoaXPress enables data rates from 625 MB/s up to 12.5 GB/s depending on the version and number of cables used.

The standard's key advantage is using readily available coaxial cable, the same cable type used for television and RF applications. This commodity cable costs significantly less than specialized Camera Link cables while supporting longer cable runs up to 40-100 meters depending on data rate. CoaXPress cameras can use single cable connections for simple applications or multiple cables for extreme bandwidth requirements.

CoaXPress version designations (CXP-6, CXP-12, CXP-25) indicate per-cable bandwidth in Gbps. A CXP-12 camera using four coaxial cables achieves 6 GB/s aggregate bandwidth, sufficient for 12-megapixel sensors running at 400+ fps or line scan cameras capturing at extreme line rates. This scalable architecture makes CoaXPress ideal for high-speed inspection, scientific imaging, and applications requiring both high resolution and high frame rates.

What Are the Differences Between CXP-6, CXP-12, and CXP-25?

CXP-6 provides 6.25 Gbps per cable (625 MB/s), CXP-12 doubles this to 12.5 Gbps per cable (1.25 GB/s), and CXP-25 reaches 25 Gbps per cable (3.125 GB/s), with each version supporting 1-4 cables for scalable total bandwidth.

CXP-6 (CoaXPress 1.0/1.1)

The original CoaXPress specification provides 6.25 Gbps per coaxial connection, delivering 625 MB/s usable bandwidth after protocol overhead. A single CXP-6 connection handles:

5-megapixel cameras at 100 fps
2-megapixel cameras at 250+ fps
Suitable for many industrial inspection applications

Cameras can use multiple CXP-6 connections for higher bandwidth. A four-cable CXP-6 camera achieves 2.5 GB/s aggregate bandwidth, supporting:

12-megapixel sensors at 166 fps
Line scan cameras with 16K pixel resolution at high line rates

CXP-6 remains widely deployed in existing installations and continues as a cost-effective solution for applications not requiring maximum bandwidth. The mature ecosystem includes numerous camera models, frame grabbers, and proven cable assemblies.

CXP-12 (CoaXPress 2.0)

CXP-12 doubles per-cable bandwidth to 12.5 Gbps (1.25 GB/s), enabling higher resolution or faster frame rates with fewer cables. A single CXP-12 connection handles applications requiring two CXP-6 cables, reducing cabling complexity and frame grabber port count.

Four CXP-12 cables deliver 5 GB/s total bandwidth, supporting:

25-megapixel cameras at 200 fps
Ultra-high-resolution line scan cameras
Semiconductor inspection and flat panel display manufacturing
Scientific imaging requiring both spatial and temporal resolution

CXP-12 maintains backward compatibility with CXP-6, allowing mixed systems where some cameras use older standards while new cameras leverage higher speeds. Frame grabbers detect camera capabilities automatically and negotiate appropriate data rates.

CXP-25 (CoaXPress 2.1)

CXP-25 provides 25 Gbps per cable (3.125 GB/s), targeting the most demanding applications. A single CXP-25 connection matches four CXP-6 cables, dramatically simplifying high-bandwidth camera installations.

Four CXP-25 cables achieve 12.5 GB/s, enabling:

100+ megapixel sensors at video rates
Line scan cameras with extreme resolution and speed
High-throughput semiconductor wafer inspection
Large-format scientific imaging
In-camera processing with full-resolution result transfer

CXP-25 represents the current performance frontier, with camera and frame grabber availability growing as applications demand ever-increasing data rates. The standard maintains the CoaXPress architectural advantages (power over cable, long cable runs, coax cable economy) while pushing bandwidth to match or exceed any competing vision interface.

Practical Bandwidth Scaling

The multi-cable architecture provides flexible bandwidth scaling. Start with a single cable for moderate requirements, add a second cable to double bandwidth, or deploy four cables for maximum performance. This granular scaling avoids over-provisioning infrastructure for applications with modest requirements while supporting growth to extreme bandwidth when needed.

Cable count also affects redundancy and system design flexibility. Some installations use more cables than minimum required, providing bandwidth headroom and allowing cable failure tolerance in critical applications where downtime is expensive.

How Does CoaXPress Compare to Camera Link?

CoaXPress provides higher bandwidth with commodity coaxial cables supporting longer distances, while Camera Link offers lower latency and a mature ecosystem but requires expensive specialized cables limited to shorter lengths.

CoaXPress vs Camera Link: Feature Comparison

Feature	CoaXPress (CXP-12)	Camera Link (Base/Medium/Full)
Bandwidth per Cable	1.25 GB/s	255 MB/s (Base), 510 MB/s (Medium), 680 MB/s (Full)
Maximum Cables	1-4 cables per camera	Single multi-conductor cable
Total Bandwidth	Up to 5 GB/s (4x CXP-12)	680 MB/s maximum
Cable Type	Standard 75-ohm coaxial cable	Specialized Camera Link cable (SDR or MDR connectors)
Cable Length	40m (CXP-6), 35m (CXP-12), 25m (CXP-25)	10m maximum for reliable operation
Cable Cost	Low (commodity coax, $2-5/meter)	High (specialized, $30-50 for 10m assembly)
Power Over Cable	Yes, up to 13W per cable	Requires separate power connection
Latency	Higher (several lines of buffering)	Lower (minimal buffering)
Ecosystem Maturity	Established, growing rapidly	Very mature, extensive camera selection
Configuration Complexity	Automatic camera detection	Manual configuration often required
Best Applications	High bandwidth area/line scan, long distances	Legacy systems, low-latency requirements

Bandwidth Advantages

CoaXPress significantly outperforms Camera Link in maximum bandwidth:

Single-cable CXP-12 (1.25 GB/s) exceeds Camera Link Full (680 MB/s)
Four-cable CXP-12 delivers over 7x Camera Link's bandwidth
Enables cameras with larger sensors, higher frame rates, or both

A 29-megapixel camera at 60 fps requires approximately 1.7 GB/s bandwidth, feasible with two CXP-12 cables but impossible with any Camera Link configuration. High-speed line scan cameras with 8K or 16K pixel arrays similarly benefit from CoaXPress bandwidth scalability.

Cable Length and Cost

Camera Link cables:

Reliably support 10-meter runs
Performance degrades beyond this distance
Specialized MDR or SDR connectors and impedance-matched construction
Typically $30-50 for a 10-meter assembly

CoaXPress cables:

Standard 75-ohm coax with BNC connectors
Available from numerous suppliers at commodity pricing
10-meter coax cable costs $10-20
Reliably support 35-40 meters for CXP-6/CXP-12

This combination of length and cost advantages suits applications where cameras must be positioned far from frame grabbers or where minimizing cable expense matters.

Power Over Cable

CoaXPress provides up to 13W power per cable over the same coax carrying data. A four-cable camera receives 52W, sufficient for:

Sensors with substantial power requirements
Active cooling systems
Eliminates separate power cabling
Simplifies installation and reduces cable management complexity

Camera Link requires separate power connections, adding cable runs and installation time. For multi-camera systems, the cabling simplification from CoaXPress power delivery becomes substantial, reducing installation costs and improving reliability by eliminating power connection points.

Latency Considerations

Camera Link's parallel data transmission architecture provides lower latency than CoaXPress, which buffers several lines of image data before transmission. For most machine vision applications, this latency difference (microseconds to low milliseconds) doesn't affect performance since mechanical system response times far exceed vision latency.

Applications requiring absolute minimum latency for real-time control loops may prefer Camera Link:

Laser processing with vision feedback
Ultra-high-speed web inspection with immediate reject mechanisms

However, the vast majority of vision applications prioritize bandwidth and cable length over minimal latency.

Migration Path

Many Camera Link installations are transitioning to CoaXPress for new deployments while maintaining Camera Link for existing systems. The significantly higher bandwidth and more favorable economics make CoaXPress the preferred choice for new high-performance applications.

Camera Link remains relevant for legacy system support and specialized low-latency applications, but new camera development increasingly focuses on CoaXPress, USB3 Vision, and GigE Vision depending on bandwidth and architectural requirements.

What Are Ideal Use Cases for CoaXPress?

CoaXPress excels in high-speed area scan applications requiring 1-5 GB/s bandwidth, line scan inspection systems with long camera-to-computer distances, and multi-camera installations where power-over-cable simplifies deployment.

High-Speed Area Scan Inspection
Applications using large-format sensors at high frame rates benefit from CoaXPress bandwidth. Semiconductor wafer inspection systems using 16-29 megapixel sensors at 60-120 fps require 1.5-3.5 GB/s bandwidth, achievable with 2-3 CXP-12 cables. The ability to capture full resolution at production speeds eliminates the choice between resolution and throughput.

Flat panel display inspection similarly demands high bandwidth for large sensors capturing defects across meter-scale displays. A 50-megapixel camera at 30 fps requires 1.5 GB/s, well within CoaXPress capabilities but impossible with Camera Link or standard GigE Vision.

Line Scan Inspection Systems
Line scan cameras in web inspection, print quality verification, and continuous material processing often require extreme data rates. An 8K pixel line scan camera capturing 200,000 lines per second with 8-bit color generates 4.8 GB/s data rate, requiring four CXP-12 cables.

The long cable lengths CoaXPress supports suit line scan installations where cameras mount on large machines or production lines with significant distance between camera positions and the inspection computer. Running 30-40 meter cables without repeaters or signal conditioning simplifies installation in factory environments.

Multi-Camera Arrays
Systems using multiple high-speed cameras benefit from CoaXPress power delivery. A quality inspection system with six 5-megapixel cameras at 100 fps requires only six coax cables total (one per camera) rather than 12 cables if power must be routed separately. The simplified cabling reduces installation time, cable tray requirements, and potential failure points.

Industrial robots with integrated vision systems use CoaXPress for in-hand cameras, with coax cables flexing through cable carriers while delivering both power and high-bandwidth data. The cable's mechanical properties suit dynamic installations better than multi-conductor specialized cables.

Scientific and Research Imaging
Research applications requiring both high resolution and high speed leverage CoaXPress bandwidth. High-speed microscopy capturing cellular processes, ballistic imaging recording projectile behavior, or astronomical imaging of transient events all benefit from CoaXPress's ability to transfer massive image streams in real-time.

The standard's flexibility allows researchers to select appropriate bandwidth for specific experiments. A researcher might use single-cable CXP-12 for standard work, switching to four-cable configuration for maximum bandwidth experiments without changing cameras or basic infrastructure.

When to Choose Alternatives
Applications with modest bandwidth requirements (under 400 MB/s) often use USB3 Vision or GigE Vision for their simpler plug-and-play installation and lower infrastructure costs. Systems requiring distributed cameras across factory floors benefit from GigE Vision's network architecture rather than CoaXPress's point-to-point topology.

Camera Link remains relevant for existing installations and specialized low-latency applications, though new deployments increasingly favor CoaXPress for its superior bandwidth and more favorable economics.

Conclusion

CoaXPress delivers high bandwidth (up to 12.5 GB/s with CXP-25) over affordable, readily available coaxial cable while providing power over the same cable connection. The standard scales from single-cable configurations for moderate bandwidth to four-cable systems for extreme data rates, offering flexibility matching diverse application requirements.

Compared to Camera Link, CoaXPress provides significantly higher bandwidth, longer cable runs, lower cable costs, and power delivery, making it the preferred choice for new high-performance vision system deployments. The growing ecosystem of cameras, frame grabbers, and development tools supports CoaXPress adoption across industrial inspection, scientific imaging, and demanding machine vision applications.

Understanding the differences between CXP-6, CXP-12, and CXP-25 enables appropriate infrastructure planning, with most new installations choosing CXP-12 for its balance of performance and maturity. As sensor resolutions and frame rates continue increasing, CoaXPress's scalable bandwidth architecture positions it as a foundation for next-generation vision systems.

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