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Cellular Modem USR-DR504 cannot Connect to the Network

This FAQ introduces the reasons for industrial modem USR-DR504 cannot connect to the network.


When the cellular modem USR-DR504 is registered to the network, the “NET” light will stay on.

Indicator functions of industrial modem

1. Check that the SIM card if it is inserted in the correct direction.

SIM card of industrial modem USR-DR504

2. Check whether the frequency band of the SIM card matches the frequency band of the cellular modem USR-DR504. At least two frequency bands match.

the frequency band of the cellular modem USR-DR504

3. If the SIM card is an APN card, please set the APN address, username, and password in the setup software.

Cellular Modem USR-DR504 cannot Connect to the Network: set the APN address

4. Whether a 4G antenna of the cellular modem is inserted.

5. Send AT command from serial port: AT+CSQ, AT+SYSINFO 

Query the signal strength and network status.

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