Westermo MR Series - Manual (Page 25)

25 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
The Escape Sequence 3.1.2
If you enter a command such as “ATD”, which results in the unit successfully establishing a connec-
tion to a remote system, it will issue a “CONNECT” result code and switch from command mode
to on-line mode. This means that it will no longer accept commands from the terminal. Instead, data
will be passed transparently through the unit to the remote system. In the same way, data from the
remote system will pass straight through to your terminal.
The unit will automatically return to command mode if the connection to the remote system is
termi nated. To return to command mode manually, you must enter a special sequence of charac-
ters called the “escape sequence”. This consists of three occurrences of the “escape character”, a
pause (user configurable) and then “AT”. The default escape character is “+” so the default escape
sequence is:
+++ {pause} AT
Entering this sequence when the unit is on-line will cause it to return to command mode but it will
NOT disconnect from the remote system unless you specifically instruct it to do so (using “ATH”
or another method of disconnecting). If you have not disconnected the call, the “ATO” command
may be used to go back on-line.
Result Codes 3.1.3
Each time an AT command line is executed, the unit responds with a result code to indicate wheth-
er the command was successful. If all commands entered on the line are valid, the “OK” result code
will be issued. If any command on the line is invalid, the “ERROR” result code will be issued.
Result codes may take the form of an English word or phrase (verbose code) or an equivalent
number (numeric code), depending on the setting of the “ATV” command. Verbose codes are used
by default. The “ATV0” command can be used to select numeric codes if required. A full list of the
Result codes is provided in the following table:
Numeric Code Verbose Code Meaning
0 OK Command line executed correctly
1 CONNECT ISDN connection established
2 RING Incoming ring signal detected
3 NO CARRIER X.25 service not available
4 ERROR Error in command line
6 NO DIALTONE ISDN service not available
7 BUSY B-channel(s) in use
8 NO ANSWER No response from remote
“S” Registers 3.1.4
“S” (Special) registers are registers in the unit that are used to store certain types of configuration
infor mation. They are essentially a “legacy” feature included to provide compatibility with software
that was originally designed to interact with modems. A full list of the registers is provided under
the section heading “S registers”.