As you can see in above picature, some of your machines may have red circle and cross icon in status. It means DTU cannot read DEX file from vending machine. This issue normally caused by following reason:
1: Machine don't support DEX.
Some of the machine can upgrade to latest version firmware to support DEX, contact your machine factory see if they have that.
2: Machine support DEX but is disabled or need do some configure to make it works.
For example, All machine made by FAS, the DEX not working by default. Have to enable it by following steps
- Goto programming mode on machine (Press a button on mother board)
- On machine keypad, input 90B then 6B.
- Press A key to select until you see RS232, then press B to save it. If alredy RS232, just press B.
- Press A to exit, turn off machine power and turn back on
You can Read machine manual or talk to their support engineer to get more helps.
3: DEX cables loose or broken.
Most of the time, vending machine will come with a data cable, one end connect to machine board, the other end is a audio socket like this.
4: Machine need power off and on