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15
Control Commands
Control Commands
The so-called AT command set established itself as the worldwide standard for modem
control command syntax (AT = command prefix Attention). The ELSA TanGo 2000 also
operates with the AT command set, permitting users of data communications equipment
to continue using a familiar command set for ISDN communications. A complete
description of the AT command set can be found on the ELSA TanGo CD. A terminal
program is required to enter AT commands via a PC (e.g. ELSA-ZOC ).
Entering and Executing AT Commands
After switching on, the ISDN terminal adapter is in the command phase. Commands can
only be accepted, interpreted and executed in this phase.
In the event that several commands are to be sent to the ISDN terminal adapter, these
may be entered individually, each with an AT command prefix and a concluding M. It
is also possible, however, to enter these commands consecutively in a single command
line after an introductory AT and to conclude the line with an M.
The individual commands may be separated by spaces to improve the overview. No
further characters may be entered once the end of the command line buffer has been
reached. The command line can then only be edited with R (backspace) or executed
with M.
Escape Command
The characters S-x and S-c may be used to abort the execution of a command
line or a screen display (e.g. when returning the contents of the registers with AT%R).
Commands that must be specified with a parameter may also be entered without a
parameter. The absence of a parameter corresponds to the parameter 0
(e.g. ATI = ATI0).
After the successful establishment of a connection to the remote station, the ISDN
terminal adapter switches from the command phase to the transfer phase.
Transfer phase means that a connection to a remote data station (i.e. to another ISDN
terminal adapter) exists: the ISDN terminal adapter is "online". This is the case after
successful call establishment (outgoing call), as well as after answering a call (incoming
call). The exchange of data between two data stations can take place during this phase.
A renewed transition to the command phase and back, also in the case of an existing
connection, is possible with the escape command and the command ATO. The escape
command consists of a series of three escape characters (default setting: +++) and a valid
command line.
ELSA TanGo 2000
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