Smart Pie vector USB async serial voltage levels

[Smartpi]

https://goldenmotor.com/SMF/index.php?topic=5967
already shows the async serial pinout diagram for the 5 pin vector USB programming cable connector.
I am troubleshooting my laptop why using goldenmotor.ca 's (latest) VEC330.zip is giving error dialogs "connecting" to the vector controller on 9600 8n1 async serial setting.
Does anyone know the voltage level of the serial TX pin? is it TTL 3.3V?
thanx