Glossary / USB-C
E-marker
The chip inside a USB-C cable that reports its real capabilities.
An e-marker is a small chip inside a USB-C cable that reports the cable's capabilities — maximum current, data speed, and vendor — to the devices on both ends. Cables rated above 3 A (60 W), and all Thunderbolt and USB4 cables, are required to carry one. Cablyst reads the e-marker directly, so it can tell you what a cable can really do rather than trusting the label.
See it on your own cable — install Cablyst, check a cable, or browse the full glossary.
Related: USB Power Delivery (USB-PD) Extended Power Range (EPR, 240 W) Thunderbolt 4 Thunderbolt 5 USB4 DisplayPort Alt Mode VDO (Vendor Defined Object) USB-IF (USB Implementers Forum) PDO (Power Delivery Object) SOP' (cable plug identity) UHBR (Ultra High Bit Rate) Active vs. passive cable