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MultliModemISI Hybrid Series, ISIHI-2S 109
Chapter 5—TERMINAL ADAPTER AT Commands, S-Registers, Result Codes
Terminal Adapter
Using AT Commands to Operate the Terminal Adapter
You can configure and operate the Terminal Adapter entirely with AT commands, if you
want. Remember, you can issue AT commands only from a terminal or from a computer
running a communications program in terminal mode. This section describes how to use
AT commands for basic operations, such as calling, answering a call, and hanging up.
Modes of Operation
The TA has three modes of operation: offline command, online command, and data.
Offline Command Mode
In offline command mode, the TA communicates with the terminal or computer and
responds to AT commands. There is no data communications link with a remote device.
Data Mode
The TA enters data mode when it makes a successful data communications link with a
remote device. In data mode, the TA can send and receive data, but it does not respond
to AT commands. Instead, it treats them as data, and transmits them to the remote
device.
Online Command Mode
In online command mode, the TA responds to AT commands while maintaining a data
communications link; however, transmission of data is suspended. To enter online
command mode from data mode, type the escape sequence +++AT<cr>. To return to
data mode from online command mode, type ATO<cr>.
Making a Call
Before you can place a data call, you must configure the TA for the local switch type,
serial port speed, and the data type of the ISDN device you want to call.
Dialing
To dial a number using AT commands, you must first start a data communications
program. In the program’s terminal mode, type ATDxxxxxxx<cr>, where xxxxxxx is the
telephone number you want to dial, and <cr> is the carriage return character that is sent
when you press ENTER , e.g, ATD7853500<cr>. The dial string can contain up to 80
characters.
To make it easier to read the dial string, you can use hyphens, spaces or parentheses.
These characters are ignored by the TA. For example, the TA would read the following
dial strings the same way:
ATD16127853500 <cr>
ATD 1-612-785-3500 <cr>
ATD 1 (612) 785-3500 <cr>
Canceling a Call
To cancel a call before the TA makes a connection, press any key.