EZ-B V3 Serial Connection Issue

It sounds like ARC is not talking to the EZ-B v3 the way it expects to.

A few important points for EZ-B v3 + ARC:

What’s likely wrong

1) The EZ-B v3 does not connect through a generic USB-to-TTL adapter

ARC expects the EZ-B v3 to be connected as a Bluetooth COM port. A USB-to-TTL adapter is not the normal connection path for this board, so ARC may see the serial port but still reject it as "not an EZ-B board."

The supported connection method for v3 is described here:

• EZ-B v3 hardware page: https://synthiam.com/Support/Hardware/EZ-B-v3
• Connection troubleshooting: https://synthiam.com/Support/troubleshooting/Connection-Troubleshooting

2) RX-to-RX / TX-to-TX is usually incorrect for serial

For normal serial communication, the lines are typically:

• Adapter TX EZ-B RX
• Adapter RX EZ-B TX
• GND GND

You said you tried swapping them, which is good, but if the adapter is just a TTL bridge, the board still may not be recognized by ARC as an EZ-B v3.

3) Powering the board after clicking Connect can cause detection failure

ARC usually expects the board to already be powered and ready before connection, especially for legacy serial hardware. Power the EZ-B first, then connect in ARC.

Most likely solution

For an EZ-B v3, the best path is:

1. Power the EZ-B v3
2. Pair it in Windows over Bluetooth
3. Find the assigned Bluetooth COM port
4. In ARC’s Connection robot skill, use that COM port

If you haven’t already, use the connection skill’s menu to configure it:

• Add the EZB Connection skill from Project > Add Robot Skill
• Open the skill’s kebab menu (three lines / menu icon on the skill)
• Set the correct COM port and baud settings there

If you must use serial

If this is some special hardware bridge setup, then I’d want to confirm:

• What exact USB-to-TTL adapter chip are you using?
• Is the EZ-B v3 actually being exposed as a Bluetooth serial port, or is this a custom serial bridge?
• What baud rate are you using?
• What does the ARC status window say exactly when it fails?

Best next step

Since this is an EZ-B v3, I’d strongly recommend trying the Bluetooth COM port method first, because that’s the connection type ARC expects for this hardware.

If you want, I can help you step-by-step check:

• the correct COM port in Windows Device Manager,
• the exact ARC connection settings,
• and whether your wiring/power setup is correct.