You awake in a small room to the sound of dozens of clocks ticking and chiming. Once you stir, you hear a familiar evil cackle over a speaker system somewhere in the room. It's the self-proclaimed "evil" Doctor Doozit, an old adversary of yours. You wonder what he has for you today.
"I see you are finally awake! Welcome to my hidden lair in the mountains. If you want to escape, you have to simply complete a couple of challenges for me. The first one is simple: tell me the time!" The doctor breaks of for a quick cackle before resuming his spiel.
"I want you to tell me the time accurate to the second. When you are ready, press the button on the wall and tell me what the time is as of pressing the button."
You look around the room. It is 4 meter x 4 meter with a small barred window on one wall. You are a bit of a camping enthusiast so you pull out your keys with a pocket knife and a compass and determine the window to be on the south wall. You look out of it and see the sun high in the sky, so roughly midday. There is a door on the north wall with the previously mentioned button on it. The east and west walls are covered in clocks with various different times set on them, obviously the doctor taunting you. Your eyes drift to a table in the middle of the room. On it is an old computer in a state of disrepair, your phone, an old chunky phone with an oversized aerial, an old alarm clock and a pad of paper with a pen. You try the old phone with no luck. As you reach for your phone, the doctor chimes in again.
"If I hear any words out of you other than the time, I will purge the room." Just as well, your phone has no signal when you switch it on anyway.
After a brief bit of work, you speak the correct time and walk through the door, much to the annoyance of the doctor.
How were you able to determine the correct time?