Good to know it’s not something simple that I missed, like using the wrong SIM. My SIM is active on the hologram dashboard, and using a much newer device I did have successful communications previously.
The primary device I am concerned with is the TK206 OBD2 vehicle tracker. There are a bunch of knock-off generics on the market, I am using a true original as my focused test device.
The primary initial mode of setup is to send an SMS to the device to retrieve vehicle location. This failed to return or report anything in the serial console on the device. If SMS is setup on these devices, you can then send an SMS messages to configure the APN.
There may be a way to configure the APN over the serial link. I am a bit of a neophyte here though, would the APN effect SMS messaging? I don’t recall needing to do this step with the TING SIM though.