From the INTERCOM.
The Big Bang Theory Season 1, Episode 1
[INTERCOM beeps]
The Big Bang Theory Season 12, Episode 13
- MAN [OVER INTERCOM]: Can I help you?
- Uh, uh, uh...
The Big Bang Theory Season 8, Episode 19
[INTERCOM BUZZES]
The Big Bang Theory Season 8, Episode 19
[INTERCOM beeps]
The Big Bang Theory Season 12, Episode 13