Avocent ESP Serial Hub Installer/User Manual page 35

Table 3.6: Modem Commands (Continued)
Command Description
Sets the value in register S0, which specifies the number of rings before auto answer.
ATS0=n
The default value is 1.
Specifies whether text or numeric codes will be returned in response to modem AT
commands and how unknown commands will be handled. Valid values are:
ATV0 = text codes will be used, unknown commands cause an error
ATV1 = numeric codes will be used, unknown commands cause an error
ATV2 = numeric codes will be used, unknown commands discarded
ATV3 = text codes will be used, unknown commands discarded
ATV
The default value is ATV0.
Table 3.7 on page 26 lists the numeric and text codes.
This command is equivalent to the Verbose Response 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 Verbose Response
option value.
Activates command mode when entered from the serial port during a remote host connection.
+++
See Command mode on page 25 for more information.
If the Verbal Response/ATV value is set to 0 or 1, any AT command other than those listed in
Table 3.6 will cause an ERROR or 4 response string to be sent to the attached serial device. Any
commands parsed up to the point of the unknown command will be processed. Commands on the
same line after the unknown command will not be processed.
For example, in the following command, V1 will be accepted, &W1 will cause an error and E0 will
not be processed.
AT V1 &W1 E0
However, if the Verbal Response/ATV value is set to 2 or 3, unknown commands will be ignored/
discarded. Commands on the same line after the unknown command, if valid, will be processed. In
the previous example, V1 and E0 will be accepted; &W1 will be discarded.
Command mode
When an ESP hub serial port is configured for the modem emulation connection method but no
TCP connection is established, the port is in command mode. When an ATDT command is
received and a session is established, the port is in data mode. Data from the network endpoint will
be forwarded to the serial port and data from the serial port will be forwarded to the
network endpoint.
The data being received from the serial port is scanned for the string that activates command mode
(+++). When this string is detected, the hub will reply OK to the device and will enter
command mode.
Chapter 3: Connection Methods, Attributes and Configurable Features 25