Dear friend!
Their USB ports usually provide the following functions:
1. Share the printer. (supported by some products)
2. Connect to a USB storage device as the public storage space.
3. Import and export configuration data and logs.
4. Uploads firmware or software during firmware or software upgrade.
5. Multimedia sharing (supported by some products)
6. Provide power for various mobile terminals.
7. Connect to the wireless network adapter (supported by some copper modems).
Thanks!