Under what conditions is an E-marker IC required in a Type-C to Type-C cable? When is an E-marker IC required at both ends of a Type-C to Type-C cable?
E-marking (having a Type-C controller) for the Type-C to Type-C cable is required under the following conditions:
- If the Type-C cable is required to support more than 3A current
- If the Type-C cable is a full featured cable i.e, if the cable either supports either USB 3.1 Gen1 or USB 3.1 Gen2 signaling
For Type-C passive cable assembly, having E-marker IC at one end of the cable would be enough. Having an E-marker IC at both ends of the cable would be required for Type-C active cable designs wherein additional electronics such as re-drivers is required to recondition the USB high-speed data signals. In active cable designs, each end of the cable can have different active function. A DFP will query the cable to know the features supported at each end of cable.