Command Mode - Equinox Systems ESP-2 MI Installation And User Manual

Table 11: Modem Commands (Continued)
Command Description
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 12 on page 19 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 18 for more information.)
If the Verbal Response/ATV value is set to 0 or 1, any AT command other than those
listed in Table 11 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-2 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.
The following rules must be followed to enter command mode:
• There must be a one-second guard time (no data traffic) before sending the +++.
• There must not be a delay longer than one second between each +.
• There must be another one-second guard time after the last +.
18 Equinox ESP-2 MI Serial Hub Installation and User Guide