your terminal emulation software (settings: 115200bps, 8, N, 1, Hardware). Now, you may
issue the
AT+IPR
command to query or change the default speed. After adjusting the port
speed, disconnect from the modem and reconnect using the new data rate. Refer to the
"Frequently Asked Questions"
section 7.0 and
"Extended AT Configurations Command
Table"
section 8.7 for more information pertaining to the
AT+IPR
command.
•
Make certain the serial cable is firmly connected to an enabled COM port with no hardware
resource conflicts. Make sure that you have properly added the "Standard 19200 bps Modem"
to your system using the
"Setting Up Your Modem"
section 2.1 above. Also, check to see if
you have an infrared (IR) port assigned to your modem's COM port. Disable it if you are not
using this function. Often, an IR port can interfere with the COM port even after you
successfully connect. Device Manager may indicate that there is no conflict between the two,
but disabling the IR port may still help.
•
If your system's COM port appears to be locked, you may have to shut down and reboot your
system.
•
Do not use "Disable Call Waiting" (commonly referred to as *70) when configuring Dialing
Properties.
•
Make certain that you are using the proper RS-232 serial cable. For most applications, you
must use a straight-through RS-232 serial cable. For certain types of equipment, you may be
required to use a null modem cable. For more information on this, refer to the FAQ section
7.12 titled
"When Do I Need A Null Modem Cable?"
.
6.1 Diagnosing COM Port Problems Using Hyperterminal
If you are experiencing problems connecting to the cellular network, you can verify if the issue is
between the computer and the modem or between the modem and the cellular network. To test,
open your terminal emulation software as described in the
"Using Terminal Emulation Software
To Talk To The Modem"
section 3.0 above. Once the modem is ready to accept commands, type:
AT+GSN
and press enter. The ESN of the modem should print out on the screen in the following
format “+
GSN: 45262036
”. This will confirm that you are communicating with the Land-
Cellular modem and not some other device connected to or inside the PC. If the ESN does not
print out, please confirm that you have selected the COM port that the modem is attached to, and
not some other port, internal modems typically show up as COM3.
To test the link between your modem and the cellular network try to call your cell phone. Type
in:
AT+CDV
<phone number to call> (with no spaces and no angle brackets) and press enter.
This command will perform a voice call similar to the type a standard home phone would make
and if your modem has been activated correctly your cell phone should ring and display the
number of the modem. Answer the incoming call on your cell phone and then hang-up your cell
phone. If you are properly communicating with the modem using the steps above and still cannot
connect through the cellular network, here are a few items to check:
•
Call the phone number of the modem. If the phone number is not active, the cellular
service will inform you of this.
•
Confirm that the ESN on the Label matches the ESN in the module with
AT+GSN
This
will print out the ESN of the Modem in Hex format,
+GSN: 45263F2A.
This rarely
happens, but if the numbers do not match, the wrong ESN may be in your Account.
•
Contact your cellular provider and make certain that the Electronic Serial Number (ESN)
of the modem is active in their system.
•
Check the signal strength reaching the modem using the following command:
AT+CSQ?
A typical reply is
+CSQ? 19,99
.The signal strength ranges from 0 to 31, the higher the
number the better the signal. See also the FAQ for more information on
"No Carrier"
issues.
