I received my Seidio 2.5mm to 3.5mm adapter in the mail today. Summary: an excellent item.
I hooked it up to the Pearl and then inserted three different sets of high end headphones that have 3.5mm plugs. All worked perfect. In fact, I am amazed at the sound the 8100 puts out.
I also had someone call me while I had the headphones on and playing music. When the call came in I pressed the Seidio's push to answer button and I successfully answered the phone.
I also could talk via the built-in microphone. An odd thing is that the music playing did NOT cut out.
Both the caller and myself could hear the music playing in the background. I do not know if that is a bug or if it was because I play my music full blast on the Pearl. For now it does not bother me since I wanted the adapter mainly to use with my headphones.
I also hooked up a cable with male plugs at both ends. Then hooked up the Pearl to some 300 watt powered speakers. Played to where I shook the windows [sub-woofer bass ].
Final test I hooked up the male/male cable to my car's MP3 player port. Pearl played fine in the car too [no surprise since the Pearl had played with the powered speakers [which were HUGE Monsoons, a great speaker system no longer made].
So all and all a fine purchase. So good I ordered another one so I can give it to a friend for her Pearl.