• Unpowered hubs are not supported, and powered hubs with more than four ports are not supported.
• USB headsets that connect to the phone through a USB hub are not supported.
Note
Each key expansion module connects to the phone counts as a USB device. If three key expansion modules
are connected to the phone, these count as three USB devices.
Cisco IP Phone 8800 Series Multiplatform Phones Administration Guide
23
About the Cisco IP Phone
USB Port Information