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6. Asynchronous Operating
6.1 General
Most of the time, you will probably use your modem with communications software, Your software will
configure the modem for you, or will offer you simple menu choices for configuring the modem. The
software will also establish and maintain the communications link for you.
If you use communications software to configure and operate your modem, you can skip this chapter.
However, if you intend to do your own programming, or if you want to set the modem's configurations
directly, you can use this chapter as a reference.
This chapter describes the asynchronous operating commands used to select options, test, and operate
the modem. These commands are based on the AT command set and extensions. Certain options are
dependent on or are restricted by the mode of operation. For example, remote DCD is not available in
the V.22 bis or Bell 103 mode of operation. Refer to
commands.
If AT commands are accidentally disabled, refer to the section called AT Command Set
Recover later in this chapter.
6.2 Command Categories
The modem offers eight major categories of command statements:
• Response
• Dial
• Terminal Interface
• Test
6.3 Operation Modes
During asynchronous operation the modem functions in one of three modes:
• Offline Command Mode
• Online Command Mode
• Data Mode
6.3.1 O
C
FFLINE
OMMAND
In offline command mode (generally referred to as command mode), the modem accepts commands
from the computer or terminal. Commands can be entered separately or in strings to change modem
options, rebuild profiles, store or change telephone numbers, and initiate or receive phone calls. There is
no data communication link established in this mode.
Commands
• General
• Remote Configuration
• Protocol
• S-registers (
M
ODE
CHAPTER 6: Asynchronous Operating Commands
for V.25 bis synchronous operating
Chapter 8
NOTE
)
Chapter 7
5 1
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