Hey Jim, thanks for chiming in. Tom H and I have been going back and forth testing comms with my OBDXPro VT.

I'm using the RealTerm open-source terminal program set for the same settings you mentioned.

After some pre-settings,
Code:
ATH1
ATAL
ATSP2
ATS1
ATSH 48 6A F0
01 00
We were able to use DS XD and then the message to communicate directly with the ECM.

Example: request freeze frame data:

DX SD 4C 10 F0 12 00 FF FF

Based on testing this morning, if you omit DX SD, you get a different answer. It's been awhile since I've read machine hex so it's all greek to me at the moment; Tom emails me commands and I email the response back. I wonder if DVI mode will obviate the need for the DX SD prefix, but it's trivial to add.

I've tested out the instruction sets available for the user guide; as an aside, being able to query the battery voltage is a nice feature. Manual available here: https://obdxpro.com/downloads/