MDB Protocol
The MDB (Multi-Drop Bus) protocol is a communication standard widely used to integrate payment terminals with vending machines and compatible devices. It enables seamless payment acceptance on MDB-capable VMCs (Vending Machine Controllers) and related peripherals.
Overview
The MDB protocol provides a standardized plug-and-play interface for accepting unattended payments on any MDB-enabled vending unit using the following Paydroid card terminals supported by Viva:
- PAX IM30
- PAX IM25
Each terminal includes an MDB connection cable in the box. Integrators simply connect the terminal to the vending machine’s MDB port—no additional configuration is required from the merchant. Viva supports MDB levels 1, 2, and 3.
What You Need
- A Viva-enabled Paydroid payment terminal (IM30 or IM25)
- An MDB interface cable or bridge (USB/RS-232 to MDB, depending on terminal model)
- Access to the vending machine’s VMC and configuration menu
Hardware adapters and pinouts vary by device vendor. Please refer to the machine and adapter documentation for specific wiring and voltage requirements.
Viva Proxy
Viva Proxy is a software component that enables Viva Paydroid terminals to communicate with external devices using communication protocols other than ECR (TCP/IP) such as MDB, ZVT, AP Concert, and others.
It acts as a software bridge between third-party applications and the Viva card terminal, ensuring smooth communication and interoperability between the MDB protocol and the terminal.
The Viva Proxy app is not pre-installed by default on compatible PAX devices. For business cases requiring Viva Proxy, please contact your sales representative or the Viva.com Support team.
In some scenarios, merchants may use their own custom proxy or MDB application. In such cases, access to Viva Proxy must be disabled.
How to Activate
Steps:
Access the Viva.com Terminal app settings
Enter the preconfigured PIN code to unlock the settings.Open the hamburger menu at the top-left corner of the Viva.com Terminal app.
Navigate to:
System > Settings > Operation Mode
When Unattended and Standalone modes are enabled, an additional setting — “Use Proxy” — becomes visible.
This setting is enabled by default.
When enabled, the unattended device communicates through the Viva Proxy.
When disable, the device operates without using the Viva Proxy.
Get Support
If you would like to integrate with Viva, or if you have any queries about our products and solutions, please see our Contact & Support page to see how we can help!