PIONEERPOS AT Commands G24-LC - Manual (Page 73)

Chapter 3: AT Commands Reference
April 15, 2008 G24-L AT Commands Reference Manual 3-9
Call Control
Managing a CSD (Data) Call
The G24-L working modes can be divided into two modes of operation.
• Data Mode: In this mode, once the G24-L has established a link with the remote modem, it
does not respond to any data passing through it (except for the Escape Sequence search). The
G24-L becomes a non-transparent link, connecting the terminal with the remote side.
• Command Mode: In this mode, the G24-L responds to the AT commands issued by the
terminal. This is the default working mode.
Note: It is possible to switch between the operating modes.
The Terminal mode allows you to instruct the modem to dial a remote modem by issuing the Dial
command followed by the phone number. You can also include dial string modifiers in your
command line to give the modem additional instructions. The following dial modifiers are
available on most modems:
• ","- Pause
Simple Dialing
In order to instruct the modem to dial a remote modem from an ordinary tone-dialing telephone
line, enter the Dial command followed by the phone number. For example, type the following
command:
ATD 876-5555 <Enter>
Note: If you receive characters which were sent, you can disable this with using the Echo
command (ATE0 <Enter>).
After issuing the Dial command, and if the remote modem answers the call, the two modems send
high-pitched carrier tones to one another which establish the transmission speed and other
parameters for the data connection. This process is called negotiation.
After the negotiation process, the message, "OK" followed by the connection speed, is received.
If the other phone line is busy, the message "NO CARRIER" is received.
If the other modem does not answer, the message "NO CARRIER" is received.
Once a connection has been established, the modem is ready to immediately begin transmitting
and receiving data. This may vary from sending messages to each other, sending or receiving
files, logging on to an information service, or any other data communication task you wish to
perform.