What is the name of Rhoda's frequently heard but almost never seen doorman on the U.S. TV sitcom "Rhoda"?

I don’t remember that he was drunken. Maybe I was too young to understand. I thought he was just incompetent.

Mars V, I thought he was high.

I had no idea!

Goioboy, me neither, but every time I hold a door for a lady, I mumble, "I'm Carlton, the doorman."