Connecting; Cellular Network; Data Network Connection; Data Communication With Remote Servers (Tcp/Udp) - Digi XBee Cellular LTE Cat 1 User Manual

Cellular connection process

Connecting

In normal operations, the XBee Cellular Modem automatically attempts both a cellular network
connection and a data network connection on power-up. The sequence of these connections is as
follows:

Cellular network

1. The device powers on.
2. It looks for cellular towers.
3. It chooses a candidate tower with the strongest signal.
4. It negotiates a connection.
5. It completes cellular registration; the phone number and SMS are available.

Data network connection

1. The network enables the evolved packet system (EPS) bearer with an access point name
(APN). See
2. The device negotiates a data connection with the access point.
3. The device receives its IP configuration and address.
4. The AI (Association Indication)

Data communication with remote servers (TCP/UDP)

Once sockets become available, communication with remote servers can be initiated in several ways:
Transparent mode data received over a serial connection (see
n
(Packetization Timeout)
API mode:
n
Digi Remote Manager connectivity begins.
n
Data communication begins when:
1. A socket opens to the remote server.
2. Data is sent.
3. The XBee Cellular Modem listens for incoming data.
Data connectivity ends when:
1. The server closes the connection.
2. The TM timeout expires (see
3. The cellular network may also close the connection after a timeout set by the network
operator.

Disconnecting

When the XBee Cellular Modem is put into Airplane mode or deep sleep is requested:
Digi XBee Cellular LTE Cat 1 Embedded Modem User Guide
AN (APN) if you have APN issues.
command now returns a 0 and the sockets become available.
for timing).
Transmit (TX) Request: IPv4 - 0x20
TM (TCP Client Connection
TD (Text Delimiter)
received over the serial connection.
Timeout)).
Connecting
and RO
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