Specifications

DM562P
Operation Manual & AT Command Set
Integrated Data/Fax/Voice/Speakerphone Modem
8 Preliminary
Version: DM562P-MA-P01
July 12, 2000
Chapter 3: AT commands and S Registers
Functional States
Configuration Profiles
AT Command Syntax
AT Command Summary
AT Command set
Status Register Summary
AT Command Set Result Codes
Example
Other Important Settings
The modem supports an extended Hayes AT command
set that allows you to adjust the modem's operating
parameters and initiate calls. This chapter describes
how to operate the modem from a personal computer or
a terminal keyboard using AT commands.
Functional States
In AT command operating environment, the modem has
four functional states:
The command state,
The wait-for-carrier state,
The on-line state, and
The on-line command state.
In the command state, the modem accepts AT
commands form the terminal, allowing you to configure
the modem and dial telephone numbers. When the
modem is powered on, it defaults to the command state.
After modem dials a number, it enters a transition state,
called the wait-for carrier state and waits for a carrier
signal from the remote modem. If the modem does not
detect a carrier signal within a preset time period (this
period is defined by the value of S7 register), it
abandons the call and re-enters the command state.
You can also cause the modem to exit the wait-for-
carrier state and return to the command state by
pressing any key on the keyboard, causing a dial abort
action.
If modem detects a valid carrier signal, it connects with
the remote modem, according to the best negotiation
speed decided by both modems, and enters the on-line
state. In this case, the modem transmits data
asynchronously. If the carrier signal is lost or
intentionally dropped the connection, the modem hangs
up and re-enters the command state.
While the modem is on line, you can temporarily exit the
on-line state, and enter the on-line command state, from
which limit set of AT commands can be entered to
interrogate the modem current settings and make sure
the connection is what is supposed to be and to
disconnect the line gracefully.
To enter the on-line command state, wait 1 second, type
+++, wait another 1 second, and type AT, carriage return
(this procedure is called Time Independent Escape
Sequence, TIES). The first valid AT commands entered
while the modem in the on-line command state will be
executed just as they would be executed in the
command state. If the first command is Invalid in this
state, it will cause modem be to on-line state and you will
have on-line connect message shown on the screen.
After the first command is accepted and in the on-line
command state, the rest AT commands will accepted
with OK or rejected with ERROR and stay in this state
until
1. You issue ATO command to re-enter the on-line
state,
2. You issue ATH to drop the connection and back to
command state,
3. Connection is disconnected and the modem go
back to command,
4. Application program request modem to disconnect
and go back to command state.
Configuration Profiles
A configuration profile refers to a complete set of
operation parameters for the modem. The operating
parameters in use at any one time are referred to as
active profile. The active profile is stored in RAM in the
modem and it may be viewed by entering AT&V. Each
time the modem powers up, the active profile is loaded
with profile 0 or 1 at the time modem was last powered
off
You can store the active profile into profile 0 or profile 1
and into the non-volatile memory (EEPROM) by entering
AT&W0 or AT&W1. So next time the modem is powered
up, you can assume the profile while you left off.
The factory default profile, which is stored in ROM in the
modem, consists of the operating parameters most
commonly used for data communication and is
satisfactory for the needs of most users. The default
profile can be reload into active profile by entering AT&F.