You should have the group pick up a USB speakerphone like Jabra makes in order to get them heard and to hear. Either that or they'll need to all connect separately to voice and sound. We had this problem and the only thing that worked well enough was separate headsets for everyone. You might have luck with the speakerphone idea, though.
This is the one I have for work, and it's awesome for a multi-directional mic: https://www.amazon.com/Jabra-Speak410-Speakerphone-Retail-Packaging/dp/B007SHJIO2
>I know there is softphone software that allows you to dial VoIP extensions from your computer but I need something that takes the audio output from the computer and routes it to the SIP channel, and takes the SIP mic channel and routes it to the computer mic channel.
sorry .. your question does not make any sense (to me at least). Do you want ... a piece of hardware that can be used for skype, gotomeeting etc.? like ... a usb speakerphone?
can you try rephrasing your question to perhaps clarify what you are looking for.
It would probably blow your budget but for this application (people sitting around a table) the Owl would be good. You might be able to find a used one. https://owllabs.com/
If you don't hate Facebook the Portal TV is actually a great piece of hardware. If you have privacy concerns you can just unplug it when not in use.
Otherwise - just use a laptop and add a decent mic and camera.
I don't have direct experience with this product but it's the one I'd chose: https://www.amazon.com/Jabra-Speak-Speakerphone-Retail-Packaging/dp/B007SHJIO2/ref=sr_1_fkmr2_4?ie=UTF8&qid=1516992292&sr=8-4-fkmr2&keywords=cisco+conference+microphone
I've used there BlueTooth device and it works great.
We use VOIP in our conference rooms which doesn't have usb: https://www.amazon.com/Cisco-7937-Microphone-Kit-CP-7937-MIC-KIT/dp/B005MQMWV2/ref=sr_1_7?ie=UTF8&qid=1516992292&sr=8-7&keywords=cisco+conference+microphone
For audio hardware, of all the various units I've tested, this one is my favorite:
For larger groups, the 710 model allows you to link 2 units:
For cameras:
Fixed, small group, tripod or display/TV top mount:
Pan-Tilt-Zoom (PTZ), Large room, tripod, tabletop, or wall mount:
Avoid this one - we purchased 10, and so far the speaker has died on 6 of them in the past 2 years:
Logitech Conference Cam BCC950
Other hardware options:
Zoom Room Recommended Hardware
For platform, if you use G Suite & have Enterprise licensing, Google Meet is fantastic, as it supports dial-in numbers and up to 50 participants. Also, it has a new hardware kit w/ touchscreen remote:
If you are nor using G Suite, then either Zoom.us or Blue Jeans would be my first pick, with a slight edge to Zoom.
For more traditional, less video-centric, powerpoint heavy platform, GoToMeeting or GoToWebinar.
Let me know if you have any questions about any of the platforms or hardware.
It does, I beta'd the GAC2500, but thats an expensive solution compared to a simple USB speakerphone that I suggested in my other comments.