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Physical Layer Description

Asset Interface

Assets will interact with the Astronode S module via the asset interface in the following ways:

  • Power: provided by the asset to the module via the 3.3V pins, or if using the RS232 option on the carrier board, by 5V.
  • Serial port: exchange messages and data via Rx and Tx lines.
  • The Event Notification pin: indicates when the module has a message for the asset. Connect to an asset GPIO input.
  • Reset pin: used to reset the module. The reset is rising edge triggered. Connect to an asset GPIO output.
  • The Wake-up pin: wake-up the module when it is in deep sleep mode. Connect to an asset GPIO output.
  • Antenna-in-use pin: for applications that will share the L-Band antenna, this pin indicates when the Astronode S module is using the antenna.

For more details of electrical specifications and how to use the pins, refer to the datasheet.

UART Configuration

The following settings shall be used for the UART:

Baud rate9600
Data bits8
Start bits1
Stop bit1
Parity typeNone
Hardware control flowNone

The UART uses TTL 3.3v levels.


The UART Rx pin (receive on the module, transmit on the asset) should not be grounded or set to high-impedance when the module is in sleep mode. In deep sleep mode, the pin can be disabled or grounded.


The Astronode DevKit exposes an RS232 port.

The port properties are the same (8N1, 9600bps) but the levels are -5/+5V.