VPOS Media | MDB Configurations Quick View
The Multi-Drop Bus (MDB) protocol defines how vending machines and payment systems communicate. Understanding MDB levels helps you choose the setup that delivers smoother transactions, faster service, and a better customer experience.
General
VPOS Media MDB Configuration Scenarios
The different MDB levels (Level 1, Level 2, Level 3) impact the operational flow of vending machines in the following ways.
Use this guide to configure your VPOS Media device for one of three MDB transaction scenarios in Nayax Core. Each scenario defines how and when a transaction starts.
Prerequisites:
- Access to Nayax Core with device configuration permissions
- A VPOS Media device assigned to your account
Choose Your Scenario
| Scenario | How It Works |
| 1. MDB Level 1 Pre-Selection | Customer taps or inserts their card, then selects a product. |
| 2. MDB Level 1 Pre-Authorization | Customer taps or inserts their card. A pre-authorized amount is charged before product selection. |
| 3. MDB Level 3 Always Idle | Device stays idle. Customer selects a product on the machine, then pays. |
Scenario 1: MDB Level 1 Pre-Selection | "Start with Card"
Card Reader Tab
| Setting | Value |
| Card Reader MDB Level | 1 |
| Decimal Place | 2 |
| Transaction Start Method | Mag+Contact+Contactless |
MDB Tab
| Setting | Value |
| Cashless MDB Address | Enable Cashless Device #1 (select the checkbox) |
| MDB Flags | 02 Pre-selection Enabled |
Payment Tab
| Setting | Value |
| Default Credit | Enabled (select the checkbox) |
| Default Credit Amount | Set higher than the most expensive product in the machine |
⚠️ Important: The Default Credit value must be higher than the price of the most expensive product on the machine. After entering the amount, select the checkbox to enable it.
Scenario 2: MDB Level 1 Pre-Authorization | "Start with Card"
Card Reader Tab
| Setting | Value |
| Card Reader MDB Level | 1 |
| Decimal Place | 2 |
| Transaction Start Method | Mag+Contact+Contactless |
MDB Tab
| Setting | Value |
| Cashless MDB Address | Enable Cashless Device #1 (select the checkbox) |
⚠️ Important: After selecting Cashless Device #1, make sure to select the checkbox to enable it.
Scenario 3: MDB Level 3 Always Idle
MDB Level 3:
- Operational Flow - This level allows for an "always idle" state, meaning the machine can start the purchasing process by allowing users to select products without requiring payment upfront. The system can handle selections first and then verify payment.
- User Interaction - Provides a more seamless user experience, as customers can browse and select items without immediate payment. This level is designed for a faster, more intuitive shopping experience, akin to traditional retail environments.
- How to Set Up MDB Level 3 Always Idle | VPOS Media
Card Reader Tab
| Setting | Value |
| Card Reader MDB Level | 3 |
| Decimal Place | 2 |
| Transaction Start Method | Product |
MDB Tab
| Setting | Value |
| Cashless MDB Address | Enable Cashless Device #1 (select the checkbox) |
| MDB Flags | 02 Pre-selection Enabled |
| MDB Level 3 Optional Features | Enable Always Idle State |
Payment Tab
| Setting | Value |
| Default Credit | Enabled (select the checkbox) |
| Default Credit Amount | Set higher than the most expensive product in the machine |
⚠️ Important: The Default Credit value must be higher than the price of the most expensive product on the machine. After entering the amount, select the checkbox to enable it.
Key Differences Between Scenarios
| Setting | Scenario 1 (Pre-Selection) | Scenario 2 (Pre-Authorization) | Scenario 3 (Always Idle) |
| Card Reader MDB Level | 1 | 1 | 3 |
| Transaction Start Method | Mag+Contact+Contactless | Mag+Contact+Contactless | Product |
| MDB Flags | 02 Pre-selection Enabled | — | 02 Pre-selection Enabled |
| MDB Level 3 Optional Features | — | — | Always Idle State |
| Default Credit | Required | Not required | Required |
Summary:
- Level 1: Requires pre-payment before product selection, making it more rigid and potentially slower for users.
- Level 2: Introduces some flexibility and allows for multi-purchase options, but still centers around pre-authorization.
- Level 3: Enhances user experience by allowing product selection without immediate payment, streamlining the purchasing process and making it more similar to retail experiences.
The choice of MDB level affects how users interact with vending machines, influencing convenience, speed, and overall customer satisfaction.
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