Using the Tesira EX-UBT

Features

Software & programming

Configurations for the Tesira EX-UBT are available from the Object Toolbar via the Telephony/Communications menu item:

 

When the Tesira EX-UBT object type is selected from the Audio Object Toolbar, the EX-UBT Initialization dialog window is displayed:

Users may check to use USB, Bluetooth or both.

USB Channel Count - This allows the user to select between three different channel configurations:

• Mono                     1 input x 1 output channel
• Stereo                    2 input channels x 2 output channels
• Multi-channel        8 input channels x 8 output channels

USB Connection Type - The two Speakerphone modes provide single or stereo audio input and output streams for use with a soft codec application on a host computer. The USB Input represents the incoming audio from the soft codec, and the USB Output is used to send audio to the far side.

Speakerphone: Disables Computer AEC – In this mode, the Acoustic Echo Cancellation (AEC) function will be provided by the AEC block in the Tesira DSP. A control message is transmitted to the soft codec via the USB link telling it to disable its internal AEC.

Speakerphone: Enables Computer AEC – This mode is for situations where the soft codec will provide the AEC function.

Line In/Out – This mode provides up to eight channels of audio. Combinations of 2, 4, 6 or 8 total USB channels can operate in fixed 24 Bit, 48 kHz.

Mute USB inputs as a group - Selecting this mutes all USB input channels when the mute state of a single input channel is changed. This selection is checked and cannot be deselected if either of the Speakerphone USB terminal types is selected. It is also checked by default if the Line In/Out USB terminal type is selected.

Mute USB outputs as a group - Selecting this mutes all USB output channels when the mute state of a single output channel is changed. This selection is checked and cannot be deselected if either of the Speakerphone USB terminal types is selected. It is also checked by default if the Line In/Out USB terminal type is selected.

Notes on host operating system controls:

• "USB host" refers to USB on the computer.
• In Multi-Channel 8x8 Line In/Out mode, changes to the USB host mute and record level controls will be ignored by the EX-UBT.
• Balance controls will not be synchronized between the USB input block and the USB host when in speakerphone mode (only playback levels are).

DSP blocks

The following images show the DSP blocks associated with different Initialization options:

          

For more details regarding EX-UBT logic, please reference tesira-help.biamp.com.

USB Details

When the EX-UBT is connected to a host computer, it will enumerate as an Echo Cancelling Speakerphone or sound device as defined during block initialization. Notice the sound device name also includes the unique serial number of the EX-UBT device by default.

     

If the user would like to change the name of the EX-UBT device as it presents to the host computer, Tesira 3.14 allows custom USB device naming within the block dialog window:

The EX-UBT device will reboot itself implementing the USB Device Name change and the host computer* will update with the new USB Device Name:

      

*(This feature had mixed results when tested on Mac OSX using 1-7 channel USB block. 8 channel EX-UBT USB block reportedly worked well.)

When the EX-UBT blocks are initialized as a speakerphone and selected as the Default Audio Device in the Windows 10 host computer, mute and volume synchronization occurs upon USB connection. This means that the host computer volume level will synchronize with the volume level of the EX-UBT USB input block in the Tesira configuration. Volume and mute changes made on the host computer or the EX-UBT USB input block will remain synchronized. This behavior is demonstrated in this short video. Note that files created with Tesira 3.17 or newer will set the USB block minimum level to -50 in order to map more accurately to the host PC volume ramp range and rate. This example video demonstrates the Tesira 3.17 behavior.

When privacy mute is selected in Skype For Business*, Microsoft Teams Room System* or Google Hangouts Meet System*, the mute state of the EX-UBT Output block mute will track accordingly. Similarly, if the mute logic input of the EX-UBT USB Output block is triggered high, the privacy mute indication in Skype For Business or Microsoft Teams will follow.

    

*The synchronization of level and mute states is possible via USB HID communication. Performance may vary with applications not listed in the UC compatibility table.

 

EX-UBT USB Tips:

• A logic-driven preset can initialize the USB input block-level providing a more consistent user experience.

  • This short video provides an example of the concept.

• Some integrated UC systems require mute state synchronization between the UC client and the table microphones. Please see this article for further details on how to accomplish this.

Bluetooth details

The Bluetooth Control/Status block offers four user-settable parameters:

• Bluetooth Name - Defaults to Tesira EX-UBTxxxxxxxx (where 'xxxxxxxx' represents the EX-UBT's serial number) and can be customized via the 'Edit' button.
• Inactivity Timeout - An active Bluetooth connection will be disconnected after the defined time period. When set to 0 seconds, a connection will not timeout.
• Bluetooth Radio - Enabled/Disabled
• Discoverable - Enables/Disables discoverability of the EX-UBT.

 

The Bluetooth Status sub-section offers additional information regarding the paired/connected Bluetooth device:

• Connected status & Bluetooth Host device name.
• Streaming status & active Streaming Profile details.
• MAC Address of the Bluetooth Host device
• Optional Disconnect button.

 

*Note, third-party control systems can poll, set, and/or subscribe to these attributes via Tesira Text Protocol (TTP).

 

Bluetooth Best Practices:

• Set the Bluetooth name to the meeting room name so that users can identify and associate it accordingly.

• Enable Bluetooth and make the EX-UBT Discoverable at appropriate times. If a conference room is powered down, it may make sense to disable the Bluetooth Radio.

• Setting the Inactivity Timeout to a value greater than 0 will automatically disconnect Bluetooth devices if they are not actively streaming. This will free up the connection if users forget to disconnect. Values between 60 and 300 are recommended.

• Setting the Inactivity Timeout to 0 seconds will allow a connected Bluetooth host to remain connected indefinitely.

• Be sure to test various sources and applications because the 'Streaming' indication may vary with each application or platform.

• Bluetooth connections are on a "first come, first served" basis. If a host device is already connected, another Bluetooth device cannot bump them off. The Disconnect button can be utilized to bump active connections and permit a new device to connect.

Gain Structure & dBFS

Bluetooth and USB source signals are digital Full-Scale signals commonly referred to as dBFS. The audio meters in Tesira software are dBu meters. The following image provides a visual for correlation:

The USB and Bluetooth sources from the EX-UBT are digital (dBFS) sources. When the host device is set to 100% volume, the signal will likely average -12 dBFS but will appear on Tesira audio meters as +12 dBu. If the host volume is set to 50%, the signal will average approximately -24 dBFS or 0 dBu.

As a point of comparison, most analog microphones have their input gain adjusted so that a good signal will meter between 0 and 6 dBu. When mixing dBFS signals with microphone or line-level dBu signals in the Tesira configuration, consider using attenuation or dynamics to level match these different source types.

The EX-UBT Bluetooth input block does include a Peak indication LED. This indicator will illuminate when the signal peak is 3 dB below clip (0 dBFS). A brief flickering of this indicator is acceptable and typically indicates the host Bluetooth device volume is likely at 100%. Turning down the volume on the host Bluetooth device will lower the signal accordingly. Based on the expected system performance, users may consider attenuating the Bluetooth input block as shown in the following image:

Powering the EX-UBT - PoE

The EX-UBT is a Power Over Ethernet device which classifies as 802.3at Class 2 (7W). Please note that there are manufacturing and design differences between mid-span PoE injectors.

When directly connecting the EX-UBT (or any Tesira expander) to a TesiraFORTE or Tesira Server-IO AVB port, the mid-span PoE injector must support 1 Gbps data link speed. If the mid-span PoE injector does not support 1 Gbps, the EX-UBT power LED will illuminate steady yellow but the LED on the AVB RJ45 port will remain dark indicating no data activity.

 

LED Indication

• Also available at tesira-help.biamp.com

Troubleshooting

Further reading

• Synchronizing table microphone and USB HID mutes
• EX-UBT Operation Manual
• Gain Structure - Further details on dBFS etc.
• Design Library example file
• http://blog.biamp.com/poe-vs-poe-the-struggle-is-real/
• Design Guide - Tesira - Open Office
• Specifying PoE Switches for Biamp Tesira devices
• Microsoft Teams Rooms Package