When docked, I hook my external microphone to the Microphone Jack on my docking station, and it works great. Wonderful and predictable sound quality.
When not docked (working remotely), I try to hook my external mic directly up to the laptop via 3.5mm jack on the left of my E6520 (labled as a "combo jack", but Windows can't seem to record sound when configured this way.
I've made certain that the "Jack Mic" Win7 device is enabled, set as the default device, and the input level is turned up.
The icon next to the combo jack on my E6520 is a pair of headphones with a microphone (a headset?). Will this jack not work with a microphone, or do I need to somehow make a config change when using this with a microphone?
I create a lot of system training screencasts, and the integrated Microphone Array is not producing the audio quality that I desire..
Combo jacks are meant for Smart Phones. I guess they are putting them in laptops because it saves a buck. To use it as intended, get a headset with an in-line mic -- it has one plug instead of two.
To use the combo jack with a regular headset or with your mic, get an adapter like the Headset Buddy. Note the 4 segmented plug in both pictures.