He paused for a moment, it hadn't occurred to him that Steven wouldn't be familiar with that.

"I suppose your technology uses a different system for ensuring communications are sent to the correct recipients. All cybertronians have a unique frequency for personal communications. It is probably a similar function to these 'phone numbers'."

He finished sending the message, coming back over to where Steven was.
"Why don't you tell me more about these Crystal Gems. It's unusual that I have never heard of them if they are a space faring people."