Desk Pro, Room Kit, Room Kit Mini, and Room 55 support USB audio devices, such as microphones and audio interfaces. The same Room and Desk devices also support USB headsets .

USB microphones and audio interfaces are supported for:

• Webex registered devices

• Webex Edge for Devices linked devices with cloud-managed software upgrades

In general, we recommend using the Cisco Webex Table Microphone or Cisco Ceiling Microphone as external microphones. These microphones are thoroughly tested with our devices and give a consistent mute behavior. However, some scenarios require, or take advantage from using external USB microphones or USB audio interfaces:

• If your device doesn’t have a dedicated microphone input, your room is slightly larger than recommended, or has challenging acoustics, an extra USB table microphone may improve performance.

• In situations with special requirements for audio pickup, for example in broadcast scenarios, shotgun or lavalier microphones might be preferred. These may be USB microphones, or require a USB audio interface in between.

• A USB audio interface also opens for more microphones, and other microphone types.

Desk Pro and Room Kit Mini don’t have dedicated microphone inputs. Hence, USB is the only option for connecting external microphones to these devices.

Configuration

When you connect a USB audio device to the Room or Desk device’s USB-A connector, the default behavior is tailored for the use of a USB headset. Both the input (microphone) and output (speaker) channels are connected, and the built-in speakers and microphones are disabled. All audio is routed to and from your headset.

When you want to use the USB-A connector for an external microphone or an audio interface you must change the Audio USB Mode setting. This setting is available in Control Hub, local web interface, and xAPI. Choose between the following values:

• Microphone: Only the USB microphone is used for audio input. Audio playback is on the built-in speakers.

• AdditionalMicrophone (only Room Kit Mini): Both the USB microphone and the built-in microphone are used for audio input. Audio playback is on the built-in speakers.

If the audio input level from the USB microphone isn’t optimal, you must adjust the Audio Input USBMicrophone Level setting (available in the local web interface).

Mute behavior

When using external Cisco microphones, the mute behavior is consistent. The mute LEDs on all microphones and the on-screen notification are all synchronized and reflect the current mute status. If you press the mute button on one microphone, also all the other microphones are muted.

When using a non-Cisco microphone, for example a USB microphone, consistency may be lost. We recommend that, when possible, the microphone should be muted from the device it's connected to.

When you mute from the user interface of the Room or Desk device, all microphones are always muted.

Recommendations and requirements

The Room or Desk devices don’t support all types of USB microphones and USB audio interfaces. These are the things to look for:

• The microphone or audio interface must support asynchronous USB audio. A diagnostics message, “USB microphone not supported. Asynchronous type is required”, is issued and displayed under Settings on the device.

• The microphone or audio interface should have a stable and linear frequency response. “Smart” signal processing, such as dynamic companding, may interfere with the performance of the device’s echo canceller and degrade the audio quality.

• A USB audio interface may require higher power than offered on the device’s USB-A port. In such cases, you must connect an external power supply.

We have tested the audio pickup quality and asynchronous USB audio support for the following USB devices.

Microphones:

• MXL AC-404

• Røde NT-USB MINI

Audio interfaces:

• Focusrite Scarlett 2i4 (2^nd generation)

• M-Audio M-TRACK SOLO

• Roland Cakewalk UA-25 EX

The provided lists aren’t exhaustive; other USB audio devices may also work with your Room or Desk device.