Lizzie Dahl: Sammy found this weird phone looking thing in his duffel. [phone rotary clicking] We think it might be a puzzle box or somethin'. We found out when you crank four it lights up, but then it goes dim 'gain with any other number after it... unless the next number is three... and then it stays lit. What we got is four, three, and now we're trying six.
Sam Kane: [phone rotary clicking, low hum] No dice. Okay... Four... [phone rotary clicking] Three... [phone rotary clicking] Seven? [phone rotary clicking] Hey! It's still lit up!
Ellie MacKay: Oh, I love a good puzzle. Scoot over. Let me see here. Oh, yeah, see... There's letters under the numbers, kids. I bet you whatever the code is, it spells a word. So...
Sam Kane: [phone rotary clicking, low hum] It's not one...
Lizzie Dahl: Hmm. Let's see then... Four, Three, and Seven... What can those spell? G-E-P?
Sam Kane: H-E-S?
Ellie MacKay: Kids... H-E-R. Her! Try seven again. Maybe its 'hers'? It could be a jewelry box or something
Sam Kane: [phone rotary clicking, phone rotary clicking, phone rotary clicking, phone rotary clicking, low hum] Nope. It ain't hers.
Lizzie Dahl: Ah, I know what it is! It's H-E-R-O! Dial four, three, seven, six. Do it, Sammy. Actually, no, let me... [clatter]
Sam Kane: Hay, I found it! It's mine.
Ellie MacKay: Let her have a try, Sam. Here... Have some chocolate. [foil crinkling, doorbell ring] I'll get that. You two play nice... [footsteps, door closing, fading footsteps]
The "Hero Dial" is an old rotary phone looking device. It's from the comic book series "Dial H for Hero". Depending on the continuity, it turned ordinary people into heroes or gave them powers, et cetera. Obviously, to properly recreate the DC Universe, the Monitor needed to make the H-Dial as well. He's just been storing it for safekeeping.