Normally in 19200,8n1 TerminalProgram: "preamble" command B1 "leave TF mode" can instruct the VEMS v3.x ECU fw to go to compat communications mode:

* (7E) B1 7F 34 (7E) is the full "B1" command, which includes the modbus CRC of B1 and the 7E frame markers.

* Man after this can be useful to enter man mode, so that some outputs (eg. warning light p259 output) can be activated from terminalprogram: in case there is a communication problem, but

** $7E$B1$7F$34$7E

** Manmdh97 switches on EC36/pin16 or ManmdhA7 or ManmdhB7 pulls the empty throughole pad of the (non populated) onboard throughole LEDs (p259/ch1, p259/ch2 and p259/ch3 respectively) next to TPIC6A259 to ground (measure VOLTAGE with DVM from +5V or +12V as a base) , see GenBoard/Manual/DigitalOut/Table => if successfully activated then it is verified that the RX direction of the serial port is functioning (either the USB-RS232 adapter or windows driver or the TX line likely has a problem if VemsTune cannot communicate despite the RX line is confirmed working).

** at least helps narrow down the problem: in any case start advanced RS232 problem-hunting in off-power state measuring continuity between processor and the ST232 or MAX232I IC; (might touch the IC while operating - should not be too hot; Total mainboard consumption around 130 mA is usually good, 180 mA is suspicious if stepper outputs are not loaded, etc...).

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