This article describes the basic physical connections required for interfacing with a Cisco TelePresence product. This article also includes disabling the AEC (Acoustic Echo Cancellation) or Echo Control and Loopback features in the Cisco codec. The article is geared toward the C40, although settings are similar for the C60, C90, and other products.
This is not meant to be an exhaustive product guide to the C40; some settings and interface screenshots in the Cisco software may change as their user interface is updated.
The SX80 is a common source of frustration as there are less options for configuration by the end user. Verify that the far end is handling echo cancellation for you. If they are routing your audio back through their codec you will hear an echo which will stop when you mute the input from the SX80.
Biamp to Cisco
An output on the Biamp device will be connected to the C40's Mic/Line In (balanced XLR) connection. This will carry the audio being transmitted (VTC Tx) to the VTC far end.
- The Cisco's Input type should be set to Line.
- Phantom power must be turned off for the C40 Mic/Line Input (defaults to off in Line mode)
- The Cisco's input level should be set to 0 (defaults to 0 in Line mode)
Cisco to Biamp
The C40's Line Out (unbalanced RCA) connection will connect to an input of the Biamp device. This input will be the audio received (VTC Rx) from the far end which will play out in the room.
- AEC, if available, must be disabled for this input channel on the Biamp (AEC is only for microphones).
- Phantom power must be disabled for this input channel on the Biamp.
- In the Cisco device, ensure that the Audio > General > SelectedOutputConnector is set to Speakers.
See the Cisco C40 physical interface guide document for further detail.
AEC / echo control
AEC can only be provided by one device in a system, in this case we are using the Biamp device. Each of the mics must be connected to an AEC input with AEC enabled.
The C40's Line Out must be connected to a Biamp input with AEC disabled, or to a non-AEC input.
The EchoControl mode (acoustic echo cancellation) must be turned Off within the C40 interface. Please see the Cisco documentation for further details - http://www.cisco.com/c/dam/en/us/td/docs/telepresence/endpoint/codec-c-series/tc6/troubleshooting_guide/tc_troubleshooting_guide_tc60.pdf