my chromebook won't recognise external hard drive or external cd player

in ChromeBook
- System:
- Battery or AC:
- Model:
- Frequency of occurrence:
- Reset OS:
- Screenshot or video:
========================
Detailed description:
0
========================
Detailed description:
Comments
Hi nigel,
Which Chromebook model are you using?
And what kind of port or cable are you using?
Thank you.