My apologies, you're right (and I say this as someone who has REed devices with an LTE modem connected over serial, so I really should have known better). But I

My apologies, you're right (and I say this as someone who has REed devices with an LTE modem connected over serial, so I really should have known better). But I would certainly still assert that the choice of the AT prefix was for compatibility rather than for line speed detection.