u-blox LARA-R203 System Integration Manual page 48

The "wake-up via data reception" feature cannot be disabled.
In command mode
always send a dummy character to the module before the "AT" prefix set at the beginning of each
command line: the first dummy character is ignored if the module is in active mode, or it represents the
wake-up character if the module is in low power idle mode.
In command mode
always send a dummy "AT" to the module before each command line: the first dummy "AT" is not ignored
if the module is in active mode (i.e. the module replies "OK"), or it represents the wake-up character if the
module is in low power idle mode (i.e. the module does not reply).
Additional considerations
If the USB is connected and not suspended, the module is kept ready to communicate over USB regardless of the
AT+UPSV settings, which have effect instead on the UART behavior, as they configure the UART power saving, so
that UART is enabled / disabled according to the AT+UPSV settings.
To set the AT+UPSV=1, AT+UPSV=2 or AT+UPSV=3 configuration over the USB interface, the autobauding must
be previously disabled on the UART by the +IPR AT command over the used USB AT interface, and this +IPR AT
command configuration must be saved in the module's non-volatile memory (see the u-blox AT Commands
Manual [2]). Then after the subsequent module re-boot, AT+UPSV=1, AT+UPSV=2 or AT+UPSV=3 can be issued
over the used AT interface (the USB): all the AT profiles are updated accordingly.
1.9.1.5 Multiplexer protocol (3GPP TS 27.010)
LARA-R2 series modules include multiplexer functionality on the UART physical link as per 3GPP TS 27.010 [8].
This is a data link protocol which uses HDLC-like framing and operates between the module (DCE) and the
application processor (DTE) and allows a number of simultaneous sessions over the used physical link (UART): the
user can concurrently use AT interface on one MUX channel and data communication on another MUX channel.
The following virtual channels are defined (for more details, see the Mux implementation Application Note [21]):

Channel 0: Multiplexer control

Channels 1 – 5: AT commands / data connection

Channel 6: GNSS data tunneling
GNSS data tunneling is not supported by LARA-R204-02B and LARA-R211-02B-00 product versions.
14 See the u-blox AT Commands Manual [2] for the definition of the command mode, data mode, and online command mode.
UBX-16010573 - R12
14 , with "wake-up via data reception" enabled and autobauding enabled, the DTE should
14
, with "wake-up via data reception" enabled and autobauding disabled, the DTE should
LARA-R2 series - System Integration Manual
System description
Page 48 of 157