Key takeaways
- Sort by who is affected before anything else: one fob, one door, or everyone at every door point to different parts of the system.
- What the reader did narrows it down, and a second fob at the same reader helps sort out a refusal from a fault.
- A fob can be switched off, expired, limited by a schedule or left half-enrolled without anyone touching it. Normally only the manager, the administrator or the service company can see or change that.
- Leave the reader, the controller cabinet and the lock closed. Report the door, the time and what the reader did.
First distinction
One fob, one door, or everyone at every door
Find out who else has the problem and where; each pattern points to a different part of the system. Where a door is held by a magnetic lock, or is a fire-rated or required exit door, the local authority having jurisdiction (AHJ) decides what is required of the locking and release hardware.
| What you find | Where to look first | Who can fix it |
|---|---|---|
| Your fob fails at every door, and other people's fobs work | The fob itself, or its record in the access system (switched off, expired, never fully set up) | The property manager or system administrator |
| Your fob works at some doors and fails at one | Your access rights or a schedule for that door | The property manager or system administrator |
| Nobody's fob works at one door | That door's reader, its wiring or power, or the lock | The service company, called by the manager |
| Nobody's fob works at any door | The controller, its power supply, the network, or a system-wide setting | The service company, with building IT if the network is involved |
| The reader signals acceptance and the door stays shut | Most likely the lock, the power feeding it, or a door that is binding in its frame. A lost reader-to-controller link can look the same | The service company |
| A brand-new or replacement fob has never worked | Enrollment, or a fob type the building's readers do not read | The property manager, then the service company if the fob type is wrong |
What the reader did
What the reader's light and beep can and can't tell you
Next, watch how the reader responds. The controller is the box in the equipment room that decides whether a fob is allowed in; the event log is its record of every attempt.
Read the response as a change from normal, not as a color. On many readers steady red is the idle state and green means accepted; on others the idle light is white or blue and red means trouble.
A light can't tell you why a fob was refused. The event log often records the reason, and the manager or administrator can open it.
Know your reader's brand? See Kisi reader lights or Verkada door reader lights for what each color means on those readers.
| What the reader did | What it usually means | What it can't tell you |
|---|---|---|
| Beeped or flashed the way it does on a good day, and the door still didn't open | The reader signalled acceptance. That often means the decision came back yes, but on some readers the signal only means the fob was read. If the link to the controller is broken, the lock never gets the command. Otherwise look at the lock, its power, or the door | Whether the lock failed or the door is simply jammed against it |
| Reacted with a different light or beep than a normal entry | The reader read the fob and the system may have refused it, or the reader may be in a fault state. Compare with other fobs and the log | Which rule refused it, if one did. The event log often has the reason |
| Was lit as usual and did not react at all | The reader may not have read the fob (a damaged fob, a fob type this reader does not read, a fob held badly, or a reader fault), or may have read it with no controller to answer | Which of those it is. A second fob at the same reader still helps sort it out |
| Showed no light at all | The reader may have lost power or failed. A few readers idle with the light off, so compare with how this one normally looks | Whether the fault is in the reader, the cable or the power supply |
| Showed an unfamiliar color or flashing pattern for everyone | The reader may have lost contact with its controller or be in a fault or lockdown state | The exact state. That takes the maker's guide for that reader |
Two-minute checks
What a resident can check in two minutes
If you are locked out right now, ask a neighbor to let you in or call the building's after-hours number. Don't prop or force a door. These checks need no tools and change nothing; do them in order.
- Try a second door you normally use. If the fob works there, the problem is at the first door or in your rights to it.
- Ask a neighbor to try their fob at the door that refused yours. If theirs works, the door and reader are probably working.
- Take the fob off a crowded key ring and hold it flat and still against the reader. Keys or a second card stacked against it can stop a read.
- Look at the fob. A cracked case, a crushed or bent body, or signs it has been through water point to a fob that needs replacing.
- Think about what changed: a new fob, a lease renewal or move, a long gap since you used that door, or a visit outside an amenity's hours all point to the system side.
- Then stop. If two or three careful tries fail, more tries won't help.
The fob
The fob itself: usually no battery, short range, not wiped by everyday magnets
A passive door fob (the usual kind) has no battery. NIST's RFID guidelines describe a passive tag as running on the energy it receives from the reader's own transmission, which is why its read distance is short. Some long-range gate tags, Bluetooth credentials and remotes with buttons do have a battery; the manager can say which you have.
NIST puts the typical range of ISO/IEC 14443 contactless cards at about 3 to 6 inches (7 to 15 cm). A small fob usually needs to be closer still, so touch it to the reader. Gate and garage credentials can read from farther away.
A passive fob keeps its number in a chip, not on a magnetic stripe, so a purse clasp, a phone or a bank card does not ordinarily wipe it.
The access system
Causes on the system side
Here the fob and door hardware are healthy, but the system has been told, on purpose or by mistake, not to open that door for that fob.
The fob was switched off or has expired
A fob can be deactivated when it is reported lost, when a lease or move-out date passes, or in a cleanup of old records. Some systems can be set to switch off fobs that go unused for a long period. The reader then refuses it at every door.
Access rights and schedules
A fob opens only the doors its group is allowed, at the times that group is allowed. Working at the lobby but not the gym is usually a rights question. One that works by day and fails at night is usually a schedule.
The fob was never fully enrolled
Someone has to add a new fob, assign it to a person and give it access, and that change has to reach the controller at each door. A mistyped number, a skipped step or a missed update leaves a fob that works at some doors or none.
The readers were replaced with a type that doesn't read the old fobs
Building fobs mostly come in two kinds: an older 'proximity' type at 125 kHz and a newer 'smart card' type at 13.56 MHz. A reader built for one kind can't read the other and usually won't react to it at all. Even within one kind, the card format has to match what the system expects.
For the two fob families, see prox cards vs. smart cards. For a lost or broken fob, see copying and replacing building key fobs.
The door and its equipment
Causes on the hardware side
Hardware faults usually affect everyone at a door, or everyone in the building. They are service-company work.
The reader has no power or has failed
A reader gets its power over a cable from the controller, a separate supply or the network. A loose connection, a damaged cable, a tripped supply or a reader worn out by weather or abuse leaves it dark or unresponsive.
The reader and controller have stopped talking
On many systems the reader only collects the fob's number and a controller elsewhere makes the decision. If the wiring between them is damaged or loose, the reader may light up and beep while nothing happens. Readers on the OSDP standard use supervised connections that indicate reader malfunctions.
The controller is offline or without power
A controller that has lost power stops every door it serves. On many systems, one that has lost its network connection keeps opening doors for fobs it already knows, while new fobs and recent changes wait until the connection returns. A building-wide failure that starts at one moment can point here.
The reader signals acceptance but the door doesn't release
You may hear a click or buzz, and the door stays shut. A misaligned door, air pressure or someone pulling early can press the latch against an electric strike, or the lock can have failed or lost power. Ease off the door, present the fob, then pull; if that works, report it, because the door needs adjusting.
What to leave alone
Don't open the reader, the controller cabinet or the lock hardware, and don't rewire, jumper or bypass a lock to get a door working. These parts carry power, and the lock is often part of the building's exit path. Don't prop the door or tape the latch either. Repairs on a magnetic-lock, fire-rated or required exit door belong to a qualified technician. See how a strike, maglock or electrified lever releases a door.
A quicker visit
What to tell the manager or the service company
These details let the manager find the event in the log. Managers calling for service can add the fob's status, the log entry for the attempt or the lack of one, and whether the door or controller shows offline.
- Which door, and whether it is one door or several
- The date and time of the failed attempt
- What the reader did: its normal accepted signal, a refusal, no reaction, or no light at all
- Whether other people's fobs work at that door, and whether yours works at other doors
- The fob's printed number if it has one, whether it is new or damaged, and anything that changed recently, such as an outage, construction or a new reader
If the fob still doesn't work
Elwin Security installs, repairs and supports card reader and key fob access control for commercial and multifamily properties in the San Francisco Bay Area. Calls are answered 8:00 AM-8:00 PM daily at (408) 539-0535.
Common questions
Apartment key fob questions
Why did my fob stop working overnight when I didn't do anything?
If your neighbors' fobs still work, the change was most likely made in the system: a fob can be switched off, expire or lose a door when a record is edited. Ask the manager to look up the fob and the log entry for your attempt.
Can I reprogram my fob myself?
In most buildings, no. A fob is added, changed and switched off in the access system, which the manager or administrator controls, not on the fob.
Will my fob work in a power outage?
It depends on the building. Systems with battery backup keep reading fobs for a while, and what each door does after that depends on its lock. Ask the manager which entrance to use during an outage.
Sources and further reading
These sources back up the general guidance. Your building and the people who approve the work decide the details for your doors.