On most apartment buzzers and call boxes, you press 9 on your phone to let someone in. Some buildings use 6, 0, * or # instead. The visitor presses your name or buzz code at the panel, your phone rings, and the digit you press sends a tone back down the line that unlocks the door. If 9 does nothing, try 6, then 0, and ask your property manager which digit your building uses.
Which number opens the door?
There is no single standard, because each building programs its own panel. These are the digits you will run into, roughly from most to least common:
| Digit | How often you see it |
|---|---|
| 9 | The most common default on telephone entry panels and gate call boxes |
| 6 | Common in older buildings and some condo systems |
| 0 | Used by a fair number of panels, especially where 9 is used for something else |
| * or # | Less common, sometimes used for a second door or a gate |
Some buildings with two doors use two digits, for example 9 for the lobby and 6 for the parking gate. If you only ever get the lobby to open, that is usually why.
Why does pressing a number open the door?
A call box is a phone that only dials residents. When you answer and press a key, your phone plays a short tone made of two pitches, called a DTMF tone. Each key has its own pair. The panel is listening for exactly one of them, and when it hears it, it releases the door strike. It is the same kind of tone as "press 1 for billing" on a support line. Our explainer on how apartment buzzers work goes deeper.
That is also why pressing the wrong digit feels exactly like a broken buzzer. Nothing happens, the visitor is still outside, and the call just keeps going.
What if pressing 9 does nothing?
Work through these in order:
- Try the other usual digitsPress 6, then 0, then * and #. Press once and wait a second each time. Holding the key or tapping it repeatedly can confuse some panels.
- Make sure the call is fully connectedIf you press too early, before the panel has finished connecting, the tone can get lost. Say hello first, then press.
- Use the phone's keypad, not a headset buttonSome Bluetooth headsets and car systems don't send key tones cleanly. Switch the call to the handset and try again.
- Check that the call is coming from the panelIf the buzz rings a landline or a roommate's phone first and they forward it to you, the tone may not survive the forwarding.
- Ask your property managerThey can read the unlock digit off the panel's settings in a minute. Write it down somewhere you'll find it.
If the call never reaches your phone at all, the problem is the number stored in the directory, not the digit. Our guide to an intercom that isn't working covers that.
How do you buzz someone in as a visitor?
If you are the one standing at the door, the steps are different:
- Find the resident's name in the directory, or enter their buzz code, the short number listed next to their unit. Our post on what a buzz code is explains where to find it.
- Press the call or bell button. On some panels you press # or the call key after the code; on others the call starts by itself.
- Wait for the resident to answer and press their unlock digit. You will usually hear a buzz or a click from the door.
- Pull the door within a few seconds. Most strikes only stay released for 5 to 10 seconds.
At a gate call box the flow is the same. If the resident gave you a gate code instead, type it on the keypad rather than calling. Our call box guide covers both.
How do you let someone in when you can't answer?
The digit only helps when you pick up. If you are in a meeting, on the subway, or asleep, the call rings out and the courier leaves. A few ways around that:
- Point the buzzer at a number that can answer for youEnterkey gives you a virtual phone number for your building's directory. When a key is active, Enterkey answers the buzz and sends the unlock tone itself, so nobody has to pick up.
- Give regular visitors a PINA cleaner or dog walker types or says a PIN at the panel, and every entry is logged.
- Share the door with your householdA roommate or partner can open the door too, even though the directory only holds one number.
When no key is active, the buzz rings your phone as usual and you press the digit yourself. Enterkey works with any buzzer that dials out to a phone number. It won't work with an intercom that is hardwired to a handset in your unit, and your property manager has to update the directory number. That is usually a one-day change. The apartment buzzer app page shows how the setup works.
Enterkey is $9.99 a month or $69.99 a year, and new members get their first 14 days free. It's on the App Store for iPhone, and Android is in open beta.
Quick answers
Is it always 9? No. 9 is the most common, but your building can set any digit. Ask once and save it in your phone's notes.
Does the visitor press a number too? Only to enter your buzz code and start the call. The unlock digit is pressed by whoever answers.
Can I press the number on a cell phone? Yes. Any phone that can make tone dialing works, including iPhones and Android phones, as long as you press it during the call.
