[headcase99]

I'm hoping you guys can help me, as I'm still learning here and have looked all over:  I have an iPhone 5 that obviously requires a 3.5mm TRRS plug.  Meanwhile, I have a mono gaming headset (splits mono across both left & right speakers) with a boom mic, and has a female 2.5mm TRS jack for connections. I've tried using a couple different 2.5mm TRS headset to 3.5mm TRRS iPhone adapters, including this one from kVconnection, but the end result always is that I can hear the incoming audio from the iPhone on the headset, but the iPhone continues to use its built-in speakerphone microphone instead of the boom mic on the gaming headset.

I suspect this is happening because although the TRRS plug is making contact inside the iPhone, the TRS connection on the other side isn't terminating the iPhone mic properly. At this point, I'm thinking perhaps its necessary to construct my own cable that has a 3.5mm TRRS male on one end, and a 2.5mm TRS male on the other end, but I'm not clear on what the connections need to be.
 
From what I've researched, the one thing I understand is that for a newer iPhone, the TRRS connection is:
 
1 (Tip) - Left
2 (Ring 1) - Right
3 (Ring 2) - GND
4 (Sleeve) - Microphone
 
If anyone can explain how I would wire a 3.5mm TRRS male plug to a 2.5mm TRS male plug on a single cable, I'd be most appreciative.  And any recommendations on what parts I need to source is certainly welcome.
 
(again apologies in advance, as I'm a newbie when it comes to DIY cables)

 

[JoshuaSee]

I ran into much the opposite situation, a piece of equipment with a 2.5mm jack that would only accept monaural headsets, and short speaker to mike on newer TRRS ones. After having to simply accept it, lo and behold I turned up an adapter packed with an el cheapo headset that worked. It was a GE 98974 headeset. It includes a couple of adapters, once of which is a 2.5mm TRS mail to 3.5mm TRRS female, which allow me to use iPhone headsets, including mike, with the older box. Combined with a somewhat easier to locate 3.5mm TRRS male to male cable, it may help in with your problem, or at least provide some insight on wiring. The headset has been sold for about $10 at Wal-Marts and discount stores, and is available online for a little more than that. Good luck