u-blox SARA-G3 Series - Page 51

SARA-G3 series - System Integration Manual
UBX-13000995 - R06 Objective Specification System description
Page 51 of 218
TXD signal behavior
The module data input line (TXD) is set by default to the OFF state (high level) at UART initialization.
The TXD line is then held by the module in the OFF state if the line is not activated by the DTE: an
active pull-up is enabled inside the module on the TXD input.