I had turned on the radios to see if I could speak with ground control to get permision for more taxi work. When the radios came up, the active radio would give a message that we had a stuck mike. After testing both the pilot and copilot headset connections, I found out that, Yes, the copilot side had a hot mike. Pulled the PTT button off to see if it was working. Here it's open and the circuit is open. That's correct.