Keep the existing controller
The machine already has an MDB cashless path. Add a machine-side board only for authorization, data, or result handling.
Guides
MDB vending integration
MDB vending machine integration guide for cashless and data projects.
Use this guide when an existing vending machine needs cashless payment, API control, or data upload over MDB. Confirm the controller's MDB version and cashless path, define the vend and result behavior, then test one machine. MDB 4.2/4.3 is the target profile; older versions and custom behavior require review and sample validation.
MDB 4.2/4.3 targetVend resultAPI + telemetrySample validation
Part of MDB Vending Machine API Gateway
MDB paths
Four common MDB project starting points.
Start with the controller and the payment path already in the machine. The correct board depends on the MDB behavior you need to control or observe.
Add an MDB-to-cloud gateway
Your server needs vend commands, MDB events, and telemetry. The board maps API commands to MDB behavior.
Add data visibility
You need heartbeat, vend result, faults, or usage data without changing the existing payment path.
Evaluate older or custom MDB
Older MDB versions or custom cashless behavior need a firmware review and a real-machine sample.
Before you choose
Check these four MDB points first.
MDB version and cashless path
Confirm the controller's MDB version and whether the cashless path is available for the project. MDB 4.2/4.3 is the target profile; older versions need review.
Vend mapping
Define product/slot, price, vend authorization, timeout, and what counts as a successful dispense.
Result and failure behavior
Confirm whether the controller reports vend success, failure, or fault events, and how the backend should handle a timeout.
Power, wiring, and payment host
Check the MDB harness, power, reader or payment host, and SIM/network requirements before the sample.
Sample flow
From machine photos to a verified vend.
Send machine photos
Machine front, controller, MDB harness, payment module, model label, and connectors.
Confirm the MDB path
Identify the controller version, cashless path, and the action to trigger.
Test one machine
Validate authorization, dispense, result, timeout, and failure behavior.
Roll out with a profile
Lock firmware, wiring, event schema, and installation notes before the fleet.
Where QuLink fits
Machine-side MDB control, not payment acquiring.
What QuLink can do
- Map server commands or payment approval to MDB cashless behavior.
- Return vend result, payment reference, fault, and device status when the controller exposes them.
- Keep the existing vending controller and reader in place for a pilot.
- Add telemetry or API control without rebuilding the whole cabinet.
What it does not replace
- Payment acquiring, settlement, or wallet balance.
- A repair service for a damaged controller or card reader.
- A guarantee that every MDB version or controller will behave the same.
- Certified electrical installation or machine safety.
Not the right fit if
- The controller has no usable MDB path and cannot be evaluated from photos.
- You need a payment acquirer rather than machine-side control.
- There is no machine, controller, or wiring information for a sample.
Interfaces and data
What the MDB path needs to handle.
- Machine interface
- MDB cashless path, vending controller, optional relay or serial auxiliaries
- Server side
- API command, webhook event, payment callback, telemetry
- Typical actions
- dispense, query_status, vend.result, machine.fault
- Project mode
- MDB retrofit, API integration, telemetry pilot, OEM controller
FAQ
MDB integration questions.
What is MDB on a vending machine?
MDB is the multi-drop bus interface used by many vending controllers and cashless devices. It carries cashless authorization and machine events; the exact behavior depends on the controller and MDB version.
Can I keep the existing vending controller?
Often yes when the controller has a compatible MDB cashless path. The sample test confirms wiring, authorization, vend behavior, and result reporting.
Is MDB always better than pulse or relay?
No. MDB can provide richer events when supported, but pulse or relay may be the practical path for older or simpler machines.
Does QuLink process the payment?
QuLink can provide an optional QR payment workflow, but it is not a bank or acquirer. You can keep your own reader, PSP, or wallet and use QuLink for the machine-side action.
What should I send first?
Machine model, controller and MDB photos, payment module, target vend action, and the data you need back.
Project RFQ
Send a machine photo. We help identify the board, interface, and next test step.
Send the vending machine model, controller and MDB photos, current payment module, target action, and expected data so we can scope the sample.
A good first message
If you are unsure about the exact interface, send what you have. Photos often answer more than a long spec.
- Machine type and target country
- Machine photo, board photo, or wiring photo
- Action after payment or API command
- Need data upload? expected quantity?
Fastest first step
- Send a machine photo
- Describe the action after API or payment
- Tell us if data upload is needed
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