13. How to Use
Microsoft HyperTerminal to Send AT Commands to a Mobile Phone or
GSM/GPRS Modem?
13.1. What is
Microsoft HyperTerminal?
Microsoft
HyperTerminal is a small program that comes with Microsoft Windows.
You can use it to send AT commands to your mobile phone or GSM/GPRS
modem. It can be found at Start -> Programs ->
Accessories -> Communications -> HyperTerminal.
If you cannot find it and you are using Windows 98, then probably you
have not installed it. You can go to Control Panel ->
Add/Remove Programs -> Windows Setup tab ->
Communications list box item -> Details button to
install MS HyperTerminal.
Before
you start programming your SMS application, you may want to check if
your mobile phone, GSM/GPRS modem and SIM card are working properly
first. The MS HyperTerminal is a handy tool when it comes to testing
your GSM devices. It is a good idea to test your GSM devices
beforehand. When a problem occurs, sometimes it is difficult to tell
what causes the problem. The cause can be your program, the GSM
device or the SIM card. If you test your GSM device and SIM card with
MS HyperTerminal and they operate properly, then it is very likely
that the problem is caused by your program.
For
Linux users, minicom can be used instead of HyperTerminal.
13.2. The Procedure
for Sending AT Commands to a Mobile Phone or GSM/GPRS Modem Using MS
HyperTerminal
To
use MS HyperTerminal to send AT commands to your mobile phone or
GSM/GPRS modem, you can follow the procedure below:
Put
a valid SIM card into the mobile phone or GSM/GPRS modem. You can
obtain a SIM card by subscribing to the GSM service of a wireless
network operator.
Connect
your mobile phone or GSM/GPRS modem to a computer and set up the
corresponding wireless modem driver. You should find the wireless
modem driver in the CD or disk that was provided by the
manufacturer. If the manufacturer does not provide such CD or disk
with your mobile phone or GSM/GPRS modem, you can go to the
manufacturer's web site and see whether the wireless modem driver
can be downloaded there. If the wireless modem driver cannot be
found on the web site, you can still use Windows' standard modem
driver.
Run
MS HyperTerminal by selecting Start -> Programs ->
Accessories -> Communications -> HyperTerminal.
In
the Connection Description dialog box, enter a name and
choose an icon you like for the connection. Then click the OK
button.
Figure
5. The screenshot of MS HyperTerminal's Connection Description
dialog box in Windows 98.
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In
the Connect To dialog box, choose the COM port that your
mobile phone or GSM/GPRS modem is connecting to in the Connect
using combo box. For example, choose COM1 if your mobile phone
or GSM/GPRS modem is connecting to the COM1 port. Then click the OK
button.
(Sometimes there will have more than one COM port in
the Connect using combo box. To know which COM port is used
by your mobile phone or GSM/GPRS modem, follow the procedure
below:
In Windows 98: Go to Control Panel ->
Modem. Then click the Diagnostics tab. In the list
box, you can see which COM port the mobile phone or GSM/GPRS modem
is connected to.
In Windows 2000 and Windows XP: Go to
Control Panel -> Phone and Modem Options. Then
click the Modems tab. In the list box, you can see which COM
port the mobile phone or GSM/GPRS modem is connected to.)
Figure
6. The screenshot of MS HyperTerminal's Connect To dialog box in
Windows 98.
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The
Properties dialog box comes out. Enter the correct port
settings for your mobile phone or GSM/GPRS modem. Then click the OK
button.
(To find the correct port settings that should be
used with your mobile phone or GSM/GPRS modem, one way is to consult
the manual of your mobile phone or GSM/GPRS modem. Another way is to
check the port settings used by the wireless modem driver that you
installed earlier.
To check the port settings used by the
wireless modem driver on Windows 98, follow these steps: a. Go to
Control Panel ->
Modem. b. Select
your mobile phone or GSM/GPRS modem in the list box. c. Click the
Properties button. d.
The Properties dialog
box appears. The Maximum speeds
field on the General
tab corresponds to HyperTerminal's Bits per second
field. Click the Connection
tab and you can find the settings for data bits, parity and stop
bits. Click the Advanced
button and you can find the setting for flow control.
To
check the port settings used by the wireless modem driver on Windows
2000 and Windows XP, follow these steps: a. Go to Control
Panel -> Phone and
Modem Options -> Modems
tab. b. Select your mobile phone or GSM/GPRS modem in the list
box. c. Click the Properties
button. d. The Properties
dialog box appears. Click the Advanced
tab and then click the Change Default Preferences
button. e. The Change Default Preferences
dialog box appears. The Port speed
field on the General
tab corresponds to HyperTerminal's Bits per second
field. You can also find the setting for flow control on the General
tab. On the Advanced
tab, you can find the settings for data bits, parity and stop bits.)
Figure
7. The screenshot of MS HyperTerminal's Properties dialog box in
Windows 98.
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Type
"AT" in the main window. A response "OK" should
be returned from the mobile phone or GSM/GPRS modem. Type
"AT+CPIN?" in the main window. The AT command "AT+CPIN?"
is used to query whether the mobile phone or GSM/GPRS modem is
waiting for a PIN (personal identification number, i.e. password).
If the response is "+CPIN: READY", it means the SIM card
does not require a PIN and it is ready for use. If your SIM card
requires a PIN, you need to set the PIN with the AT command
"AT+CPIN=<PIN>".
Figure
8. The screenshot of MS HyperTerminal's main window in Windows
98.
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If
you get the responses above, your mobile phone or GSM/GPRS modem is
working properly. You can start typing your own AT commands to
control the mobile phone or GSM/GPRS modem.
Further
details about how to use AT commands to send and receive SMS messages
will be provided in the following sections.
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