Multi-Tech Systems ISIHP-4U Topic, Description, Command Implementation , p AT, Command execution

Terminal Adapter AT Commands & S-Registers

ENTER. On the other hand, if you are configuring a communications program, you typically must insert the carriage return character by adding ^M to the end of the command string.

The TA has three modes of operation: offline command mode (the default state), online command mode, and data mode. The TA responds to AT commands only when it is in one of the command modes. After the TA establishes a connection and goes online in data mode, it interprets any further characters you enter as data rather than commands and transmits them to the remote device.

When the TA is in data mode, you can switch it to online command mode by sending it an escape sequence. The TA responds to two types of escape sequences: in-band (escape sequence is part of the data stream) and out-of- band (escape sequence is outside the data stream). The in-band escape sequence is +++AT<cr>; the out-of-band escape sequence is <break >AT<cr>. You can change the in-band escape character (+) by changing the value in register S2. You can send the break signal in the out-of-band escape sequence only from software, not by pressing SHIFT+BREAK on your keyboard.

When it detects the escape sequence, the TA enters online command mode, in which it responds to commands while maintaining the connection with the remote device.

The TA ’s command buffer can store 80 characters, including spaces and other characters used in telephone numbers. If you mistype a command string, you can edit it by using the backspace key, but only before you press ENTER. As you type a command string, it appears on your monitor screen, letting you verify your input as you type it.

AT commands recognized by the ISIHP terminal adapter are listed by function on the following page. For an alphabetic list of AT commands, see AT commands in the index. The commands in this chapter are organized by function. Abbreviated commands are listed on the following page by function along with a short description and page numbers that refer to a more detailed description, immediately following this list.

Topic	Command	Description
Command Implementation, p. 107AT		Attention code
	Return	Command execution

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