I bought 1x OptiPlex 7070 SFF and 1x OptiPlex 7080 SFF from different sources recently (and I have 7-8 other Dell, HP and Lenovo laptops and desktops at home, and I used to build PC's for fun, so I am not a newbie). Both 7070 and 7080 computers were installed with Win 11 Pro from scratch (deleted all disk partitions), updated with the latest drivers from Dell, and updated to the latest Windows update. Device Manager doesn't show any issue with any device.

The problem is, when I plugin any headset, I can hear sound just fine, but microphone doesn't work!! This happens to both computers, and I have tried different brands of headsets, all with TRRS plugs that work just fine on other computers or phones. I also tried the front audio port and the back port (although the manual labels the back port as Audio Out only).

"Microphone doesn't work" means the computer doesn't sense a mic has been plugged into the front audio port, so doesn't show my headset as a possible selection in various apps. I can verify this in Control Panel -> Sound, I have 3 devices listed:

1. Microphone, HD Pro Webcam (this is my webcam that has a mic, mic works)
2. Jack Microphone, Realtek Audio, status = not plugged in (this is the front plug, it is showing OS doesn't see a mic!!)
3. Stereo Mix, Realtek Audio (this was disabled after the clean install, I enabled it, didn't make a difference)

I assume...

• There is only 1 audio port in the front, so it is TRRS style, otherwise, there is no place to plug in a mic in the front.
• Given these are fairly new models, both front and back audio ports can't be Audio Out only.
• I assume the design is NOT Mic only in the front and Audio Out only in the back.

I thought I got a bad motherboard initially, but the fact 2 different models from 2 different sellers have the same problem makes me think I am missing something really simple. Can someone help?