SM4 and SDL3 comms sharing.

[supercharged88]

I was wondering if i can parallel the RX and TX and earth signals from the SM4, to be able to share the data between the SDL3 and my laptop at the same time.
Would there be any comms issues with Baud rates etc.
Sometimes when tuning in the race boat and i have the laptop hooked up,the driver feels blind without his tacho etc.
It would be great to have them working at the same time.

[DarrenR]

It should be ok, but i can't say for certain given it's the Autronic ECU driving the signal.

Won't hurt to try. You only need to splice the TX from the ECU to the dash's RX pin, otherwise the ECU is connected to the the laptop as normal.

[supercharged88]

Thanks for the reply.
I'll give it a go in the next week or so and let you know if it works.

[bazeng]

I don't think it will work. Let me know how you go.

The proper way is to connect the ecu to your laptop, and use a secondary com port to connect your laptop to the sdl. There is an option in the sm4 software to select your datastream output port.

[Holmz]

Generally you will want to have a ground as a twisted pair with both the TX and the RX.
I usually float only on one end, and ground the other end..
Then those two ground wires can be tied together at whichever end you ground at.

The mitigates magnetically induced interference on the lines... especially cross talked interference between the two as they are generally running parallel in the same sheath.