Multi-Tech Systems ISIHP-2U - Manual (Page 105)

MultiModemISI Hybrid Series, ISIHP-2S/2U/4S/4U/4SD 105
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