Chapter 3 – Using Your Wireless Modem
30
Multi-Tech Systems, Inc. MultiModem GPRS USB Wireless Modem User Guide
Establishing a Circuit-Switched Data (CSD) Connection
A Circuit-Switched Data Connection (CDC) makes the wireless modem work similar to a regular analog
modem. You must have CSD service in order to make a CSD call.
Note:
Your cellular provider charges airtime usage for these connections.
1.
To establish a Connection:
a.
Open HyperTerminal or a terminal application.
b.
Type
ATD<phone number>
Notes:
●
The phone number you are calling is entered between the displayed brackets. Do not type
additional brackets. For example, type only
ATD 8585551212
.
8285551212
between the brackets.
●
This command tells the modem to inform the wireless network that you are initiating a CSD modem
call. If you are dialing to another modem, the remote modem should answer and a connection
between the two modems will be established. If you include a semi-colon (;) at the end of the dialing
string, the modem will instead initiate a Voice call to the phone number dialed.
2.
To disconnect:
a.
Type:
+++
b.
Wait about two seconds to see an OK response.
c.
Type
ATH
Note:
+++
is the escape sequence and
ATH
is the Hang-up command.
Answering a Circuit-Switched Data (CSD) Connection
A Circuit-Switched Data Connection makes the wireless modem work similar to a regular analog modem.
You must have CSD service in order to answer a CSD call.
There are three phone numbers for GSM: the voice number, the data number, and the fax number. All
are provided by the carrier. To answer a call:
1.
To establish a connection, call into the modem by dialing the data number provided by your carrier.
2.
To answer a call, when you see the RING responses on the terminal screen, enter
ATA <cr>
.
3.
To set auto-answer:
a.
Enter ATS0=x
where
x
is the number rings
This sets the modem to auto-answer. The call will be answered after the number of rings
entered. .
b.
Then call into the number provided to you by the carrier.
4.
To disconnect:
a.
Type
+++
b.
Wait about one second to see an OK response.
c.
Type
ATH