You're right, it's the latter. Yeah, you can still use the keypad after the call is started. But it's a little clunky. The instructions you have to give people are like "first dial 542, then wait until you hear the prompt, then enter code 867". Which as it turns out is a little too complex for a lot of people. Another reason why it wouldn't have been great as a paid product.
You could also have a fallback that forwards the call to your cell phone after a failed attempt at entering the code. But most of the reason I built this was so it would stop calling me at random times, so I didn't really want that.
Yeah, the call box in general is just not a great system in my experience. I often just tell guests and delivery people to text or call me when they get there, which works for me because my apartment is very close to the lobby. Itβs just easier than hoping they figure out how to use the call box and follow my directions to get to my apartment.
You could also have a fallback that forwards the call to your cell phone after a failed attempt at entering the code. But most of the reason I built this was so it would stop calling me at random times, so I didn't really want that.