4. What are the accessories? Is the cable interchangeable?

Abundant accessories

JD1 earphones*1, 3.5mm to 0.78 2pin cable with microphone*1, Ear tips S/M/L*3 pairs (M pre-installed), User manual*1

[Cable]

The JD1 features a 0.78 2pin detachable cable that allows ample opportunities for future upgrades.

And the cable is not compatible with 0.78 headphone with flat or recessed connector. But the unit is compatible with FiiO's cable series and Bluetooth ear hooks with detachable 0.78 connectors.