Installation guide

Rev 1.1 9/22/14 29
Getting Started
Communicating with the
USR3500
Table 7. Basic AT Commands to Use with the USR3500
AT Command
Description
AT+CGMI
To check if the serial port is OK
The USR3500 will respond with "Sierra Wireless" when it is OK.
AT+CPIN=xxxx
To enter a PIN code, xxxx (if activated)
AT+CSQ
To verify the received signal strength
AT+CREG?
To verify the registration of the USR3500 on the network
6.2. Verifying the Received Signal Strength
The USR3500 only establishes a call if the received signal strength is strong enough.
Using a communication software such as HyperTerminal, enter AT+CSQ to check the
received signal strength. The response returned will follow the format +CSQ: <rssi>,
<ber>
where: <rssi> = received signal strength indication, and <ber> = channel bit
error rate.
Refer to the table below for the description of the <rssi> values returned.
Table 8. <rssi> Value Description
<rssi> Value
Description
0 – 10
Received signal strength is insufficient
11 – 31
Received signal strength is sufficient
32 – 98
Not defined
99
No measure available
6.3. Verifying the Network Registration
Using a communication software such as HyperTerminal, enter AT+CREG? to verify the
network registration of the USR3500. Refer to the table below for the list of main
responses returned.
Table 9. AT+CREG? Main Reponses
AT+CREG? Response
Description
AT+CREG: 0, 0
Not registered
AT+CREG: 0, 1
Registered on the home network
AT+CREG: 0, 5
Registered on a roaming network
If the USR3500 is not registered on the network, do the following: