Apple Express Fax/Modem - Manual (Page 124)

Modem states
The Express Modem has two functional states: command state and on-line
state. Command state allows you to enter commands that control the modem,
such as configuration parameters. In command state, the modem is not
capable of sending or receiving data. In on-line state, the modem sends and
receives data through the telephone system. To enter commands from the AT
command set, the modem must be in command state.
Moving between command and on-line states
When the modem is turned on or after reset, the modem always goes to
command state. It automatically enters on-line state after successfully making
a connection with a remote modem, either when answering or originating
a call.
While the modem is in on-line state, you can issue a command that takes it
back to command state. When you control the modem in this fashion, it is in
local command state. While in local command state you can send commands
to the modem from your keyboard.
1 Open your communications software program, and choose the option that lets you enter
AT commands.
Consult the user’s guide that came with your software to find out how to enter
AT commands from your keyboard.
2 Type the escape sequence +++.
Wait one second (or a period equal to the guard time set in register S12).
Do not type any other commands or make entries before or after the escape
sequence while you wait. After a moment the message OK will appear.
You may now enter AT commands. Once you have done so:
m To go back to on-line state, type ATO.
m To hang up, type ATH.
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