Cable-Tester

MDB connector Pin Out

MDB vending machine connector’s pin out

Introduction to MDB

MDB is a communication standard used in the vending machines industry to interlink numerous devices used in a vending system. It is one of the common standardised vending used around the world today. You can typically find this MDB connector connection in the following types of machines.

  • Cold/Hot Drinks Vending Machines
  • Toy Catchers Machines
  • Coffee Dispenser Machines
  • Packet Snacks Vending Machines
  • Hot Food Baking Machines

Another vending standard is VCCS. It is adopted by the vending industry in Japan. Vending machine from Japan manufacturers typically uses VCCS instead of MDB interface standard.

MDB Connector details

Peripheral Connector

Molex Mini-Fit Jr 5569 Series, 6 ways (buy part number: 39-30-1060)

Available from Digikey part number: WM1353-ND

Master (VMC) Connector

Alternative connectors available

Tools Accessories

  • MOLEX 11-03-0044 Extraction Tool for Mini-Fit Jr Crimp Terminals
    Available from Digikey: WM9918-ND

MDB Communication Protocol Documentation

Also known as MDB ICP (Multi Drop Bus, Internal Communication Protocol). The following are the details containing the communication protocol standard used on the MDB connection interface.

Serial Communication Configuration:
9600bps NRZ, 1 Start Bit, 8 Data Bits, 1 Stop Bit, 1 Mode Bit, no hardware handshaking. 0-5V signal (TTL level).

The mode bit is a special 9th bit in the communication protocol, acting as an indicator to finish up an ongoing communication.

MDB Interface Circuit & Signal

The MDB interface is in a pull-up pull-down voltage and open-collector configuration. This allows the interface to other devices without being too much affected by the voltage system that the other devices are deployed with.

MDB interface circuit & signal

The signaling is pretty similar to the serial communication UART. You can implement MDB using the UART from the microcontroller. MDB protocol has a mode bit that uses the 9th bit of the UART serial protocol standard.

For data monitoring of this special serial data with a 9th bit, you can use Docklight serial terminal software to view. The software allows the configuration of the 9th bit. This allows you to monitor the MDB data communication. Not all the terminal software on the market allows configuration for the MDB communication protocol.

The VMC (or master device) controls the communication, to poll for slave response. Response from the slave device must be within a time frame of 5msec.

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Chinese Cable Tester

This page introduce the Cable Tester available from Chinese market. Most of the tester are in China are using Chinese language. You can contact us if help is needed for translation to English. We can try to support you.

These are low cost cable harness wiring connection tester. It allows testing of any type of cables for up to 512 connection points.

LCD Display Screen

Display will show the cable test result “Pass” or “Fail”.

It can also shows the pins that are connected and those that are left unconnected.

The user menu are however in Chinese language. A little translation will be good good to start using this cable tester.

Expandable I/O for more wire connection testing

The cable tester comes with expandable test points. Each expandable board allows testing of additional 64 connection points.

A maximum of 8 expandable boards can be stack together with the tester processor main board. This allows up to a maximum of 512 connection points.

Software display of test result

The tester main board can be connected to a computer system (Windows operating system) via the RS232 communication port.

From the software, you can see more detailed information of the cable test result from tester board.

The language is currently only in Chinese version only.

Other cable testers available in the market

JH_CABLE_ADJ, https://item.taobao.com/item.htm?id=604786144142

LT_CABLE_L40, https://www.taobao.com/list/item/595530482540.htm

OS_LT21, https://www.taobao.com/list/item/648770131003.htm

CT-9909-64, https://item.taobao.com/item.htm?id=565159705959

JH_RES_ADJ, https://www.taobao.com/list/item/596950606247.htm

ICT_LT20A, https://www.taobao.com/list/item/611110355490.htm

ICT LT21, https://www.taobao.com/list/item/648770131003.htm

ICT LT22A, https://item.taobao.com/item.htm?id=683405013665

LW-8681, https://detail.tmall.com/item.htm?id=627149695743

LW-3310, https://item.taobao.com/item.htm?id=672791125565

DY760, https://item.taobao.com/item.htm?id=627428126057

DY8680A, https://item.taobao.com/item.htm?id=627428126057

DY260FA, DY260N, https://item.taobao.com/item.htm?id=654563252110

MICROTEST 8740, https://item.taobao.com/item.htm?id=658834857471

384P, https://item.taobao.com/item.htm?id=628063237138

BL-DC256, https://item.taobao.com/item.htm?id=634984380330

???, https://item.taobao.com/item.htm?id=537381611412

9910B, https://item.taobao.com/item.htm?id=728524253335

Cable Connection Tester CT-9809, CT-9909, https://pcdetail.taobao.com/85c5f826d9cf3b15c8ff82a390cef920.html

Aigtek ATX-100 Wire Harness Tester, https://item.taobao.com/item.htm?id=678220190293

CJ-8001, CJ-8005, CJ-8683FA, CJ-9001, CLE-8002-80, CLE-8002-128, CLE-8060-128, CLE-8060-256, CLE-8060-512, https://item.taobao.com/item.htm?id=35644586943

DSJ-9809L, https://www.aliexpress.com/i/1005005767648092.html

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Cable Tester Selection Guide

The most basic requirement for needing a cable tester is for testing of the wiring connection. You can quickly and easily test whether if an automated machine makes a connection or if your operator has make the correct connection through manual wire assembly. If you can only going for simple connection testing, you can simply click here and check out these small portable cable tester.

For comprehensive testing of your cable, this is where you will need a high-end cable tester equipment. You will need to understand the exact type of test that you want to do on your assembled cable.

  1. Wire connection of the cable.
  2. Resistivity and conductance of the copper wire. (maximum current)
  3. Insulation of the jacket around the copper wire. (maximum voltage, HiPot test)
  4. Cable capacitance between the copper wires.
  5. Data speed bandwidth of the cable.
  6. Cable impedance
  7. Electrical characteristic testing (capacitors, diodes, or resistors detection)
  8. Mechanical physical testing (elasticity, bend-ability)

2. Advanced Electrical and Performance Testing

When higher reliability or compliance to specific standards is required, a high-end cable tester becomes necessary. These systems go beyond simple continuity checks and can measure multiple electrical and mechanical parameters.

a. Wire Continuity and Mapping

  • Verifies that every conductor is correctly connected, without shorts, opens, or miswiring.
  • Essential for multi-pin connectors, custom harnesses, or complex assemblies.

b. Resistivity and Conductance

  • Measures the resistance of the copper wire to ensure it can handle the specified current.
  • High resistance indicates poor-quality wire, loose crimps, or long runs that may cause power loss.

c. Insulation Resistance & HiPot Testing

  • Tests the quality of insulation around conductors by applying a high voltage (HiPot).
  • Ensures that no leakage or breakdown occurs, preventing electrical hazards.
  • Common in medical devices, aerospace, and industrial power systems.

d. Capacitance Testing

  • Measures the capacitance between adjacent wires.
  • High capacitance can degrade signal quality, especially in high-frequency applications.

e. Bandwidth and Data Rate Testing

  • Evaluates the cable’s ability to support specific communication speeds (e.g., Ethernet, USB, HDMI).
  • Confirms compliance with data transmission standards.

f. Impedance Testing

  • Ensures the cable maintains the correct characteristic impedance (e.g., 50Ω, 75Ω, 100Ω) for RF or high-speed digital signals.
  • Prevents reflections and signal loss.

g. Electrical Component Detection

  • Some testers can identify passive components such as resistors, capacitors, or diodes accidentally embedded in the wiring.
  • Useful for troubleshooting custom electronic assemblies.

h. Mechanical and Physical Testing

  • Evaluates elasticity, bendability, and strain relief of cables.
  • Helps ensure long-term durability, especially in robotics, automotive, or environments with frequent flexing.

3. Choosing the Right Tester

  • Simple builds (consumer electronics, office cabling): A portable continuity tester is sufficient.
  • Complex assemblies (aerospace, automotive, medical): A high-end tester with full electrical and mechanical diagnostics is required.
  • Data cables (Ethernet, HDMI, USB): Use a tester that includes bandwidth, impedance, and compliance checks.
  • High-reliability industries: Consider testers with automated test reporting, traceability, and compliance certification features.

Other cable testers available in the market

Our Best Selling cable tester

Click here to check out our in-house cable connection tester.

Affordable, small, portable and lightweight. Powered by USB.

CCT-01 Cable Tester Tool
Click here to check out our cable tester tool.