The installation created by Dan Horan invites passersby to use the phone without dialing a number or expecting someone to answer on the other end in the traditional sense.
Instead, participants are encouraged to share their thoughts, memories, and emotions.
The project drew widespread attention after a young boy's emotional message to his mother in heaven went viral.
"Hey, Mom, I know you're up there in heaven, watching down on me. My brother Zy passed away," the boy said in a recording captured at the installation.
Horan said the moment occurred on the first day he set up the phone at LOVE Park.
For the past week, he has offered visitors an opportunity to express what is on their minds.
Some of those conversations have focused on personal struggles and hardships.
"Things are still hard; they're expensive. It's hard to make ends meet," one woman said before breaking down in tears.
Horan said the project taps into a type of human connection that has become less common in an era dominated by digital communication.
"You used to be able to feel how excited or sad or mad somebody was when you picked up the phone and answered them, and now it's all through text or message or, like, through status. And you can't feel that energy unless it's, like, some weird emoji, you know?" Horan said.
He said the simple act of using a traditional telephone appears to encourage people to open up.
"For some reason, that phone - just picking it up. It brings out that energy that we all used to have when we would pick up the phone 20 years ago and talk to another," Horan said.
Horan said he has conducted social experiments around the city for the past two years.
He plans to continue the phone installation at LOVE Park and in Northeast Philadelphia at Frankford and Cottman, weather permitting.