“I just walked through — so how is my fare calculated so precisely?”
These days, when using public transit in Seoul or Incheon, you’ve probably seen fares go through without anyone touching a card or phone to the reader.
This is Be-In Be-Out (BIBO) — a hands-free, contactless fare payment method Tmoney brands as Tagless. Today, we’ll break down how it works, and the technology behind it.
1. What is Be-In Be-Out (BIBO) payment?
Be-In Be-Out — known in Korea by Tmoney’s brand name “Tagless,” and elsewhere as hands-free fare payment — is a next-generation contactless fare payment method that automatically recognizes boarding and alighting and charges the fare, without touching your transit card or smartphone to a reader.
The conventional method — Tap-In Tap-Out — required you to tap your card precisely on the reader. BIBO removes that tapping motion entirely. Walk through the gate with your smartphone in your bag or pocket, and the system recognizes you and processes the fare on its own.
The key is that it has to be accurate without any physical contact. It’s not enough to simply detect a user — the system must calculate, without error, who boarded and alighted at which station and when, so the fare is correct. Delivering that accuracy is the essence of this technology.
2. How is it built?
At its core, Tmoney’s Be-In Be-Out payment uses your smartphone’s BLE (Bluetooth Low Energy) to enable payment without any tapping. However, the implementation differs between rail and bus.
1) Rail
① BLE signal exchange
Your smartphone and the gate exchange BLE (Bluetooth Low Energy) signals. Through these signals, the system detects that “this user is now passing through this gate.” As the name suggests, BLE consumes little power, so it can run continuously without straining your smartphone battery.
② Precise positioning via smartphone
BLE alone can tell that you’re “nearby,” but not exactly which gate you’re passing through. So Tmoney combines smartphone positioning technology to pinpoint the user’s location. Even when several gates sit side by side, it identifies which one you pass through.
③ Gate integration to confirm entry and exit
Finally, integration with the gate confirms the user’s entry and exit.
With these three steps working together, the system recognizes your boarding and alighting stations without any contact and calculates the fare automatically.
2) Bus
Buses have no fare gates, so the approach is different.
On buses, a beacon installed inside the vehicle communicates with your smartphone via Bluetooth to automatically detect boarding and alighting.
Even with your smartphone tucked in a pocket or bag, simply getting on and off the bus is enough — the app determines whether you’re inside or outside the vehicle and monitors this continuously. Instead of a physical passage point like a gate, the vehicle itself becomes the recognition space.
To further improve payment accuracy, the bus’s operation data is also used. For example, to prevent unintended payments while the bus is moving between stops, payment is processed only when the vehicle has arrived at a stop.
In short, rail relies on BLE + positioning + gate integration, while bus relies on BLE beacon + vehicle operation data + app integration — each implemented differently to suit the transit mode, all to deliver accurate fare payment without tapping.
3. Why is accuracy the heart of the technology?
In public transit payment, accuracy matters most. If a fare is miscalculated, trust breaks down.
Because Be-In Be-Out lacks the definitive signal of physical contact, it secures accuracy by layering multiple technologies. That’s how your fare is calculated correctly even as you walk through without taking out your phone.
It also runs in parallel with the conventional tap method. At stations without BIBO gates, on transfer routes, or on buses not equipped for it, you can still use the traditional Tap-In Tap-Out method — so users can choose based on the situation.
It’s a design that adopts new technology while maintaining compatibility with existing infrastructure.
4. Proof of a mature technology — expanded deployment and global awards
Whether a technology is still at the lab stage or genuinely proven shows in where it’s deployed and how it’s evaluated.
1) Service expansion
Tmoney’s Be-In Be-Out technology has expanded step by step, validating along the way. Starting with the Ui-Sinseol light rail in 2023, it extended to all stations of the Incheon subway and Line 7 (Seongnam, Incheon), a Seoul city bus pilot route, and full operation on Seoul Subway Line 9 (Gaehwa–Sinnonhyeon). Being applied across different transit modes — light rail, subway, and bus — means its stability has been verified in a wide range of environments.
2) Recognition on the global stage
Tmoney’s Tagless (Be-In Be-Out) technology won the top award two years running — at the 2023 UITP (International Association of Public Transport) Global Public Transport Summit Awards and the 2024 Transport Ticketing Global Awards. For a Korean technology to earn the highest evaluation from the global transit and payment industry two years in a row is a clear indicator that it is world-leading.
5. What this technology changes — the travel experience
The value of a technology is ultimately measured by the change it brings to people. Be-In Be-Out makes changes like these:
- Eases rush-hour congestion: The stop-and-tap motion at the gate disappears, so the flow speeds up.
- Convenience for travelers with luggage: You can pass through without stopping, even while carrying a suitcase or pushing a stroller.
- Better mobility for those who need it: It’s especially helpful for users who find tapping difficult — those on crutches or in wheelchairs, and older passengers.
In other words, it goes beyond “convenient payment” to create an environment where everyone can move more smoothly.
6. Tagless is a symbol of Tmoney’s technology
Be-In Be-Out removes the long-held assumption that you must “tap.”
Two consecutive years of global awards show that Tmoney’s Tagless (BIBO) technology is a proven, next-generation transit payment system. Tmoney continues to expand this technology, leading the way toward the future of public transit payment.
