Usually you telecommunications application controls and configures your telecommunications card (the modem). However, you can also control and configure most modems, including your telecommunications card, using a "language" called the AT command set.
You control and configure your telecommunications card from within a telecommunications application. You can enter an AT command to "tell" your telecommunications card to perform a variety of tasks, such as dialing or answering the telephone. For example, to get the telecommunications card's attention and ask it to dial a phone number such as "123-4567," enter the following command line:
ATDT 123-4567
Today, many Macintosh telecommunications application contain options for dialing, terminal emulation, and file transfer using menu commands that are in plain English. However, in many telecommunications applications, the AT command line appears on your screen after you choose the menu command.
Uses for AT Commands
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At commands have a number of uses. You can use AT commands to connect to a certain type of modem. You can also use AT commands in scripts. A script is a set of AT commands you use to perform a certain function. You often use scripts to automate common activities, such as logging to an on line service.
Command state and On-line State
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When the telecommunications card is on, it is always in one of 2 states: the command state or the On-line State. The telecommunications card assumes the command state when power is turned on. In the command state, AT commands are sent to the telecommunications card to control all aspects of its operation. After your telecommunications card connects with a remote modem, both the telecommunications card and the modem are in the on-line state. All information you send to you telecommunications card is sent to the remote modem as well.
Command Buffer
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The command buffer is the area in which you enter At commands. The command buffer capacity for the telecommunications card (platinum V) is 39 characters. If the command line exceeds the command buffer capacity, the telecommunications card will not execute the command line and will send an ERROR message after the carriage return. If you exceed the character limit, re-enter the command with fewer than the allowed number of characters so that the command line can be executed.
You can enter telephone numbers with or without punctuation: for example: (123) 456-7890 or 1234567890
Punctuation in the telephone number takes up space in the command buffer. Note that the AT command characters, the space character, the carriage return control character, and the line feed (LF) control character are not stored in the command buffer.
AT Command Components
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The following sections discuss the key components of an AT command.
* Attention Code
You must begin command lines with the characters "AT" and enter them as all uppercase (AT) or all lowercase (at) characters. The attention code (AT) gets the telecommunications card's attention and indicates that the text following the AT command is a command that the telecommunications card should act on. The following is a sample command in which you instruct the telecommunications card to hand up: ATH0
* Command Parameters
Most AT commands have parameters - single-digit or double-digit options - that follow the command letter. Each command has a default parameter. The default parameter is used if no parameter is specified. For example, the "Hn" command has 2 parameters: 0 and 1. The command defaults to 0 if no parameter is specified. Therefore, typing ATH is equivalent to typing ATH0.
* Return Key
You must end the command line with a carriage return. Press the Return Key to enter a carriage return. The telecommunications card begins executing a command when it receives a carriage return.
* Delete Key
Before executing a command by pressing the Return key, you can edit the command using the Delete key. The Delete key cannot erase the AT at the beginning of the command line.
| General Global Village Command list |
| Command | Meaning |
| ATDT phone nu | ATDT and a telephone number dials a telephone number using a touch tone dialing. |
| ATE1 | Ensures that commands you send to the telecommunications card appear on your screen when you type them. |
| ATH0 | Hangs up the line. |
| ATM0 | Turns off the modem speaker. |
| ATLM1 | Turns on the modem speaker while dialing until connection is established |
| ATX1 | Ignores the dial tone when dialing a number. |
| ATV1 | Displays verbal results codes, such as RING, CONNECT, OK, and NO CARRIER. |
| ATZ | Resets the telecommunications card to its power-on configuration. |
| AT&F1 | Resets the telecommunication card for optimal high-speed connections. |
| ATDP | ATDP and telephone number dials the phone number using pulse Dialing. |
| Teleport Gold II, Gold IIv and Platinum V |
| ATL1 | Sets the speaker volume to low. |