Echo in calls

[firesting]

So basically when I speak on the phone with someone else using another incredible s, we both hear our own voices, an echo. Speakerphone is fine, headset is fine. If one of us is using a landline, its fine as well. Only when we're both using our incredible s. The only way to keep it to a minimum, is to turn the volume way down. Anyone have similar issues and remedies? Thanks!!
Oh I almost forgot to mention, we're both running an unlocked version on the rogers network and both phones are on the providers android version 2.2.1

 

[firesting]

So I upgraded both phones to ARHD and S-OFFed the phone and now everything is working great!