Phillips and other soldiers were battling insurgents last week when his phone pressed against his humvee and inadvertently dialed his parents in Oregon.
Their answering machine recorded three minutes of the battle.
"Once I realized that they heard it, I just felt real bad for them having to hear that. That's something they shouldn't have heard, and I'm just happy I got a hold of them to let them know I was OK," Phillips said.
Phillips had been in Afghanistan for about a year.