My main use of this adapter is to connect my 3rd Gen iPod Touch to my van's audio system. The van has built-in Bluetooth and when call comes in to my conventional cell phone, the audio is cut off. This is bad because like to listen to podcasts and don't want to miss material. This used to result in lot of fumbling around to flip open the Griffin folio case and stop playback. After the call, would have to re-position in the podcast to resume listing. (Traffic lights seemed to delight in staying green just to prevent me from having the moments required reposition/restart safely.)
This adapter very nicely solved that problem. When call comes in, can pause iPod playback with one click of the button on the adapter, without even touching the iPod or its case. When the call is over, another click resumes playback. Besides the play/pause function of single clicking, quick double click advances to the next track. It's not quite hands-free, but close. can click it without taking my eyes off the road. One thing that this adapter lacks that some others have is volume control up/down buttons. In the attached screen shots, the IPHMICEXT is clipped to 3.5 mm stereo to RCA phono adapter which feeds the van's audio inputs.
The marketed function of this device is to add microphone and start/stop/next track functions to an existing set of headphones/earbuds for IOS devices. must point out that it also works very nicely for recent Macs too. I've used this adapter with my 2009 MacBook Pro (MacBookPro5,5) to add those same functions to plain set of headphones. Works nicely with iTunes and Skype. haven't tried it, but it seems my Mid 2011 Mac Mini also has iPhone audio support. You can check out the Audio section of System Profiler/About This Mac to see if your model has iPhone audio support. (See screen shot.) I've also used my MBP with the NewerTech Hands-Free Mic & Earbuds (IPHBUDMIC) as well as the Apple earbuds that came with my iPod Touch.