A second SIM card for your apartment buzzer: what it costs and what it still misses

A thread on the Public Mobile community is titled "Getting a new sim for Intercom in a Condo apartment". The problem behind it is common. Your cell number came from another city, and the condo’s entry panel will only dial a local one. So you buy a second line just for the lobby. It is a fair fix. Before you buy it, know what it costs over a year and what it still leaves broken.

Not sure whether your number is local to your building? Check it free in ten seconds: your postal code and the first six digits are enough.

What actually solves the problem people buy a second SIM for?

The real problem is not the SIM. Your building’s entry panel stores one phone number per unit, and it usually needs that number to be local. The rest of the problem is about who picks up when it calls. Why your buzzer only rings one number explains the one-number limit in more detail.

BuzzMeBro gives your apartment its own local phone number. You hand it to your building once, and the building stores it in the lobby panel like any other number. When a visitor buzzes, every phone registered to your apartment rings at the same time, up to 4. Whoever answers first talks to the visitor and can open the door. The door-open digit is usually 9, but your building sets it.

A buzz arrives as an ordinary phone call. There is nothing to install to receive one. Setup happens once on the website. The price is $9.99 a month or $95.00 a year, billed per apartment, not per person. A local number is checked at signup. If none is available for your building yet, you go on a waitlist.

How much does a second SIM for the buzzer cost per month?

Here is the honest math on Public Mobile, the carrier from that thread. These are its 2026 prices, and carriers change them often.

So the line costs close to $25 a month once tax is added. That is a full phone plan doing one job. Nobody else ever calls that number. It exists so the lobby has something local to dial.

Prepaid plans also have to be paid on time. If a renewal fails, the line can be suspended, and the next buzz reaches nothing. You tend to find out when a courier has already left.

BuzzMeBro is $9.99 a month, or $95.00 a year, which works out to $7.92 a month for the whole apartment. The subscription is the only thing BuzzMeBro is paid for, with no advertising and no tracking cookies or pixels, and the privacy policy says in writing that customer data is never sold or used to train AI models.

What does a second SIM still not do for your buzzer?

A second line fixes the local number. It does not fix who answers. Three things stay broken.

A second SIM rings one handset

A SIM lives in one phone at a time. When the lobby calls that SIM, one phone rings. If you live with a partner or roommates, only the person holding that phone hears the buzz. Your food is in the lobby, your roommate has the buzzer phone, and your roommate is at work.

Some people forward the buzzer line to their main cell. Forwarding sends the call to one other number. It does not ring two phones at once. How to make a buzzer ring two phones at once covers why.

The buzzer phone has to be charged and nearby

If the second SIM goes in an old phone, that phone has to stay on. It has to be charged. It needs signal where you are. And someone has to hear it. An old phone on the kitchen counter does nothing when you are in the shower, at the gym or out for the day.

Most people carry two phones for a few weeks, then stop. The buzzer phone ends up dead in a drawer, and the driver leaves with your parcel. What to do when an Amazon driver cannot get into your building is the usual next search.

A new cell line still gets spam filtered

The second SIM is a cell line like any other. Carrier spam filtering now often sends lobby panel calls to voicemail. A panel calls many numbers briefly from a line nobody calls back, and that looks like spam. A brand new SIM does not change that. Why your buzzer goes to voicemail walks through the fix on your phone.

When is a second SIM a reasonable choice?

Sometimes it is fine. If you live alone, your phone takes a second SIM or an eSIM, and you want to keep your out-of-town number, a second line in your own phone works. The buzz rings the phone you already carry. You pay for a plan, but you skip the second device. Buzzers and out-of-province numbers explains why the building wanted a local number in the first place.

That setup stops working the day someone moves in. It rings you and only you. A partner, a roommate or a subletter cannot answer it, and you become the person who opens the door for everyone.

How do you replace a buzzer-only SIM with a number the whole apartment can answer?

1. Check that a local number is available Start at signup. A local number for your building is checked there. If none is available yet, you join a waitlist, so keep the SIM running until you have a number.
2. Add the phones in your apartment Register up to 4 phones. Each one rings at the same time when someone buzzes.
3. Give the new number to your building Send it to your property manager or concierge once. They store it in the entry panel in place of the SIM number. Changing the phone number on your buzzer has a message you can copy.
4. Test it from the lobby Buzz your own unit. Check that every phone rings and that the door-open digit your building uses opens the door.
5. Cancel the second line Once the test works, cancel the prepaid plan so you stop paying for a number nobody calls.

A second SIM gets your building a local number. It costs close to $25 a month with tax, and it rings one handset that has to be charged and near you. BuzzMeBro gives your apartment a local number that rings every registered phone at once, for $9.99 a month per apartment. You can check whether a number is available for your building.