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SX20 third party mics and Polycom soundstructure c-series


We are trying to connect a SX20 microphone port to the output of a Polycom soundstructure C12.
I'm wondering if anybody has been successful doing this?

It looks like the SX20 has to be tricked to believe its microphone is connected.
Maybe by sending some power on some pins?

I've seen several example on how to connect powered mics directly to the SX20 but the soundstructure output port is different and the codec keep the port shut when plugging it in.

Has anybody been able to connect a soundstructure or similar device to a SX20?




22 Replies 22

On the SX20 under

Settings->Administrator Settings->Advanced Config->Audio->Input->HDM1->Mode Off

Shawn Jones



Is this still working after recently released software updates from Cisco for the SX?

We are running TC7.2.1 and it is still working fine.


If you look under Audio Input Level on the SX20, the Mic is reported as Disconnected for us.
Don't use this as a way to tell if your Mic is working or not.

Thanks, I will pass it along to our folks.

Wow. So you are saying that even though the sx20 microphone level shows as disconnected, audio is passing?  How can I confirm this without a second codec?  I need to hook up a biamp nexia real soon.



We use BlueJeans

Dial or (enter meeting ID 111# and # when prompted). You'll see a parrot. Talk to him, and he'll repeat.

The voice is distorted to sound like a parrot I guess. But that will confirm that your Mic is able to transmit.

Thank you. Can't wait to try it!

or puts you directly in to the conference.

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