Jaton Communicator V.90 - Manual (Page 44)

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CHAPTER 5 AT COMMANDS
Overview
The modem (DCE) operates in two states: command or online. In each
mode, both data and commands (including DCE responses) are transferred
through the UART THR (Transmit Hold register) and the RBR (Receiver
Buffer register).
The modem defaults to the command state. In this command state, the host
(DTE) communicates to the modem through AT commands and S-registers.
S-registers contain modem status and configuration information that DTE
can access. AT commands are character strings that guide modem
operation. Many of AT commands indirectly affect the contents of S-
registers.
•
An AT command string begins with an AT prefix and ends with a
carriage return character defined in S-Register 3 (default: <
↵
Enter>).
The A/ (repeat last command) and +++ Escape sequences are the only
exceptions.
•
AT command strings can contain multiple commands in the same
string. These commands are placed after the AT prefix and before the
<
↵
Enter>. Spaces may be used to separate commands within the string.
•
Each command line may include up to 80 characters and spaces.
•
The AT prefix and commands may be in either upper or lower case, but
all characters for the given command must use the same case.
•
For commands that contain numeric options you may omit the numeric
value and the modem will assume that the number 0 was entered.
•
While the modem is attempting to connect to a remote modem, any
character entered is considered an ABORT command. The modem will
go on-hook and enter the command mode.