Digi XBee 3 Cellular LTE-M, User Manual, Page: 160 / 331

Socket behavior API mode behavior for outgoing UDP data
Digi XBee® 3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide 160
The device sends a Transmit (TX) Status - 0x89 frame in reply to the Transmit TX Request indicating
the status of the request. A status of 0 indicates the connection and/or data was successful, a value of
0x32 indicates a temporary Resource Error (see Socket limits in API mode ), and other values indicates
a failure.
Any data received on the connection is sent out the XBee Smart Modem's serial port as a Receive RX
frame.
A connection is closed when:
n
The remote end closes the connection.
n
No data is sent or received for longer than the socket timeout set by TM (IP Client Connection
Timeout) .
n
A Transmit TX Request is sent with the CLOSE flag set.
API mode behavior for outgoing UDP data
To send a UDP datagram to a remote host, send a Transmit (TX) Request: IPv4 - 0x20 frame to the
XBee Smart Modem's serial port specifying the destination address and destination port of the
remote host. If you use a source port of
0 , the device creates a new socket for the purpose of sending
to the remote host. The XBee Smart Modem supports a finite number of sockets, so if you need to
send to many destinations:
1. The socket must be closed after use.
or
2. You must use the socket specified by the C0 (Source Port) setting.
To use the socket specified by the C0 setting, in the Transmit TX request frame use a source port that
matches the value configured for the C0 setting.
The device sends a Transmit (TX) Status - 0x89 frame in reply to the Transmit TX Request to indicate
the status of the request. A status of 0 indicates the connection and/or data was successful, a value of
0x32 indicates a temporary Resource Error (see Socket limits in API mode ), and other values indicates
a failure.
Any data received on the UDP socket is sent out the XBee Smart Modem's serial port as a Receive (RX)
Packet: IPv4 - 0xB0 frame.
A UDP socket is closed when:
n
No data has been sent or received for longer than the socket timeout set by TM (IP Client
Connection Timeout) .
n
A transmit TX Request is sent with the CLOSE flag set.
API mode behavior for incoming TCP connections
For incoming connections and data in API mode, the XBee Smart Modem uses the C0 (Source Port)
and IP (IP Protocol) settings to specify the listening port and protocol used. The XBee Smart Modem
does not currently support the TLS protocol for incoming connections.
Note For NB-IoT, TCP support is dependent on the network. Contact your network provider for
details.