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ProxyServer User Guide
Using AT Commands to Operate the ProxyServer
You can configure and operate the ProxyServer entirely with AT commands, sent from a terminal or
from a computer running a communications program in terminal mode. This section decribes how to
use AT commands for basic operations, such as calling, answering a call, and hanging up.
Modes of Operation
The ProxyServer has three modes of operation: offline command, online command, and data.
Offline Command Mode
In offline command mode, the ProxyServer communicates with the terminal or computer and
responds to AT commands. There is no data communications link with a remote device.
Data Mode
The ProxyServer enters data mode when it makes a successful data communications link with a
remote device. In data mode, the ProxyServer 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 ProxyServer 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 ProxyServer 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 the ENTER key; e.g.,
ATD7853500<CR>. The dial string can contain up to 80 characters.
To place an ML-PPP call, use an ampersand character (&) to join two telephone numbers; e.g.,
ATD7853500&7853502<CR>. The telephone numbers can be the same or different. Using this
method, two B-channels are activated to transmit data at an aggregate speed of 128 Kbps.
To make it easie to read the dial string, you can use hyphens, spaces, or parentheses. All these
characters are ignored by the ProxyServer, and all the following dial strings are equivalent:
ATD16127853500 <CR>
ATD 1-612-785-3500 <CR>
ATD 1 (612) 785-3500 <CR>
Channel Bundling Flag Dialing
The command AT&Jn is used to indicate whether outgoing calls should be made on two B-channels
by default. The command AT&J1&W0<CR>, configures the ProxyServer to place a call dialing on
two B-channels by default; if no second number is given in the dial string, that single number is dialed
twice. This is done to compensate for the interworking issues with Windows 98/95. On the other
hand, if the user explicitly indicates two numbers in the dial string, then two numbers are dialed (e.g.,
ATD7853500&7853502<CR>). The command AT&J0&W0<CR>, disables automatic call bundling.
Note other valid characters joining two telephone numbers include a Plus Sign (+), and an
Exclamation Mark (!).
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MTPSR1-202ST
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