MP3 Headset to Headphone Jack Question

[C-2]

So I hear they have these new thingies out called MP3's (lol)...I am trying to hook up an MP3 player, via a cassette adapter (with a male 3.5 mm stereo jack), to an older car. I hooked up the neighbors MP3 and it sounded great.
However, now I am trying to get our phones to play MP3's via the same cassette adapter. The phones are a new MotoRazr2, and a new LG Chocolate.
I purchased a 2.5mm stereo to 3.5mm stereo jack, but when using the phones, sound is coming from 1 speaker only. I notice of I back the jack out, it plays in stereo. Same prob going to the home system using either phone, and two separate jacks (to eliminate my first theory I had a bad or mono jack).
What is the deal with 2.5 headset jacks coming out of phones?
I also seee both phones are Bluetooth compatible - should I buy a Bluetooth audio adapter?
Anybody know?
Thanks in advance.

[Phat Matt]

What's a "cassette"?

[73kona455]

why not just get one of the deals that plugs in and broadcast it to your radio? they sell for about $20

[Tom Brown]

What is the deal with 2.5 headset jacks coming out of phones?
I also seee both phones are Bluetooth compatible - should I buy a Bluetooth audio adapter?
Anybody know?
Go to an electronics store like Best Buy, Circuit City, or whatever. They will have the adapter you need.
I have no opinion on bluetooth audio as I've never used it.

[Trailer Park Casanova]

We searched you tube and several kids had solutions they demonstrated and they taped.

[Cheap Thrills]

Are you sure all the jacks/adapters are stereo ? If one is mono it will do what you are describing.
Stereo Jacks have 3 rings. mono jacks have 2.
If you're an audio purist, you wont be happy with the frequency response or the S/N of an RF modulator designed to broadcast in the 88~108 Mhz range.
Bluetooth is also RF but it's frequency response & S/N is slighty better but not by much.
Good Luck
T.