people generally say "it's me at the door". Is it incorrect to say"This is me at the door".Do both convey the same meaning?
What goes wrong if one says the latter sentence?
"This is me at the door" sounds more natural and correct to me.
"It's me", is what I'd say, and usually do say. The alternative, "This is me", wouldn't cause confusion or a misundertsanding. However, it's rather odd given that the pronoun "this" refers to something close to the speaker.
If you're using a speaker phone, be it attached to your apartment wall, or a desk phone at the office, or even your home phone or a cell phone, then, yes, "This is me" works just fine. It's short for "This is my voice you're hearing" and/or "This is the person you wanted to speak to."