Installation guide

Rev 1.1 9/22/14 38
Getting Started
Troubleshooting the USR3500
Table 19. Receiving a “No Carrier” Message
If the USR3500
returns
Then ask
Action
“NO CARRIER”
Is the received signal strong enough?
Refer to section 6.2 Verifying the
Received Signal Strength to verify the
strength of the received signal.
Is the USR3500 registered on the network?
Refer to section 6.3 Verifying the
Network Registration to verify the
network registration.
Is the antenna properly connected?
Refer to the Reference Guide at
http://www.usr.com/support/3500 for
more information about the USR3500’s
antenna requirements.
Is the band selection correct?
Refer to section 6.5 Switching Bands for
more information about switching
between bands.
"NO CARRIER"
(when trying to issue
a voice
communication)
Is the semicolon (;) entered immediately
after the phone number in the AT
command?
Ensure that the semicolon (;) is entered
immediately after the phone number in
the AT command.
e.g. ATD######;
"NO CARRIER"
(when trying to issue
a data
communication)
Is the SIM card configured for data calls?
Configure the SIM card for data calls.
(Ask your network provider if
necessary).
Is the selected bearer type supported by the
called party?
Ensure that the selected bearer type is
supported by the called party.
Is the selected bearer type supported by the
network?
Ensure that the selected bearer type is
supported by the network.
If still unsuccessful, try selecting the
bearer type using the AT command:
AT+CBST=0,0,3
If the USR3500 returns a “NO CARRIER” message, you may retrieve the extended
error code by using the AT Command AT+CEER. Refer to the following table for the
interpretation of extended error codes.
Table 20. Extended Error Codes
Error Code
Diagnosis
Hint
1
Unallocated phone number
16
Normal call clearing
17
User busy
18
No user responding
19
User alerting, no answer
21
Call rejected
22
Number changed
31
Normal, unspecified