This is great advice but it also brings up a point; why do these systems require a local number in order to operate? It seems that a firmware upgrade could possibly decimate the op's business.

Edit: I want to point out that I am in no way, shape, or form saying that the op could not make a decent amount of money on this(though, 10/month is a touch steep for someone living in an apartment) but I was just curious why the manufacturers of such devices limit them in such a way.

Guessing they want a local number because the apartment complex doesn't want to pay for long distance calling.

For us it was specifically because they didn't want people opening the door remotely. They wanted you to be local.

I haven't paid for long distance calling since the 1990s. I think it's just people being lazy and choosing poor defaults.

How many of these buzzers have remained unchanged since the 1990s?

Also, long distance appears to be at least $20/month extra on a standard small business landline here (Bell Canada). That's not much, but I can see it happening for something the landlord would think of as a non-feature: Because why wouldn't you have a phone number in the area you live?

I'm not sure a small business line is the best comparison for an apartment building, and I think most landlords are familiar with the existence of cellphones by now. But it's true that many buzzers like that have been in place for a long time - but I do think that that's the landlord's problem, like any other non-working fixture.

A firmware upgrade could probably decimate the OP's business, but the whole value is that this service may be a lot cheaper in terms of mental effort and stress for many landlords.

Some of them don't. I currently have an out of state number and the door entry system has no problem dialing it.

If I was paying rent, and now I had to pay more money to open the door, that would probably deter me from renting from this building. Almost like a protection racket... You might be a tenant, but cough up extra money to get into your apartment... I would strongly discourage a landlord from trying something like this. This is not a typical upsell, if anything the tenant blames the landlord for the problem in the first place...

Read the article. The service is for an enhanced way of opening the gate, not for opening it in the first place.

The perception of offering charging for any type of access to your apartment enhanced or not would be perceived negatively. Consider an apartment where the landlord charged you $1 every time you want to use the elevator, but you can always walk up the stairs. While one might be an enhanced way, I think people would still view it as the landlord double dipping. I think this product is much more suited to be a promotional feature subsidized by an outside delivery company (pizza joint) or the landlord to show off fancy bells and whistles in his building to entice new renters.