Robust coms connection

[See_Mos]

Hi Tim, I had to chuckle at some of the answers.  some good ideas but not what you require.

My suggestion would be to use Ser in / out or HSer in / out and use low value resistors at both ends.  You could go as low as a few hundred ohms but even a few K would reduce the chance of sticky fingers or noise upsetting things.

[trastikata]

Sorry If I sound rude but I did explain in my first post "TTL" I have reiterated it several times.
....
I'm going from one PCB to another. I have no need to introduce a CAN or any system like it to talk to a PCB 50mm away.

No offense taken Tim, it simply wasn't clear what are your requirements. It seems a standard Digital Isolator might be what you need instead of SN74LVC2G07, like for example ADuM251N from which you can even receive samples if it is for prototyping all you need. 

[TimB]

Thanks trastikata

That ADuM251N looks very useful.

[See_Mos]

ADuM251N

Nice price if you need complete isolation but overkill otherwise.

How many channels do you need and is the ground or VSS common to both boards?

[TimB]

Hi Trevor

Reviewing my needs I have the following needs.

TX
RX
1 Digital channel.

I could just run on the main boards 3.3v VDD
VSS is common.

I went for 12v as that will be a common power rail. Putting a regulator on boards makes it easier to use in other locations. I think I will have to use the hardware USAT as I will have an interrupt RX system. For the once in a blue moon config set up it may get.