Cisco 8800 Series Administration Manual page 39

About the Cisco IP Phone
Note • 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.
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
USB Port Information
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