Since the earth Stargate rotates, why isn't the incoming address known?

[sunnyrio]

I'm sure on occasion they've said they don't know who just called them. Can't they just watch the symbols?

[Joe]

No caller ID display?

[sunnyrio]

Ah, I'd do what I do on my mobile. Block unknown callers and don't let them leave messages either. This really annoys the hospital trying to give me an appointment. I sent in an official complaint telling them I wouldn't open my front door to someone wearing a balaclava.