Avocent ESP Serial Hub, Installer/User Manual, Page: 34 / 96

24 ESP Serial Hub Installer/User Guide
Modem commands
Table 3.6 lists the supported AT modem commands. All other AT commands will be ignored or
cause an error, depending on the configured response code and verbose response settings. With the
exception of the ? and ATDT commands, multiple commands may be entered on the same line,
separated by a space. (If a question mark is entered on a line with other commands, it is interpreted
as AT?. If an ATDT command is followed by other commands on the same line, ATDT will be
recognized, but the remaining commands on the line will be ignored.)
Information about command mode follows the table.
Table 3.6: Modem Commands
Command Description
? Help. Displays a list of valid AT commands.
AT? Returns the value of register S0.
ATA Instructs the ESP hub to answer an incoming call.
ATDT< ip >[,|:]
< socket>
Initiates a TCP connection to the specified host. A comma, period or nothing may be used to
separate IP address octets. TCP ports may be delimited by a comma or colon.
For example, the following commands are all valid:
ATDT 10,100,128,129:3001
ATDT 10.100.128.129,3001
ATDT 010100128129:3001
The IP address and socket number are required unless they were configured when the
modem emulation connection method was enabled; see
Modem Emulation Connection
Method Configurable Items on page 21.
The dialout translation feature may be enabled to translate from an input string (usually a
telephone number) to an IP address/IP port; see
Dialout translation on page 27.
ATE
Enables (ATE0) or disables (ATE1) echo mode. The default value is ATE1.
This command is equivalent to the Echo option that is specified when configuring the modem
emulation connection method. If you issue this command with a value that differs from the
configured option value, the new value will override the configured value only for this
connection. Subsequent connections will use the configured Echo option value.
ATH
Disconnects the network session. The ESP hub will close the active TCP session and return
the appropriate code (No Carrier or 3), depending on the ATV value.
ATO
Returns the ESP hub to data mode. When the hub returns to data mode, it once again listens
for incoming data from the ESP hub at the other end of the connection. The remote hub will
then send any data it may have stored.
ATQ
Enables (ATQ0) or disables (ATQ1) response codes. The default value is ATQ0.
This command is equivalent to the Response Codes option that is specified when configuring
the modem emulation connection method. If you issue this command with a value that differs
from the configured option value, the new value will override the configured value only for this
connection. Subsequent connections will use the configured Response Codes option value.