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AT Command Operation
COMMAND SCOPE
Supervisor Command Mode
8-4
Some commands use special formats or have special rules
concerning their use. For example, the dial D command
initiates the dial process so no other commands, only dial
modifiers, can follow the D command.
The scope of a command refers to the extent of its effect on the
TA. AT commands have a scope of Global, Channel, or Port.
Global commands affect the operating characteristics of the
TA as a whole, potentially disrupting operation on all of the
ports and channels. Thus, a global command should be used
with caution (or not at all) if there are currently active calls on
any port.
Channel commands affect only the operation of the B1, B2, or
D-Channels of the TA. These commands should be used with
caution if there are active calls on any port.
Port commands affect only the operation of the particular DTE
port in use. If the user is issuing a port command via DTE port
1, then only DTE port 1 characteristics are affected. This rule
does not apply if the user has entered Supervisor Command
Mode (explained in the next section).
The UTA220 is equipped with a feature called "AT Supervisor
Command Mode." This allows AT commands issued from one
DTE port to be executed as if they were coming from another
DTE port. This includes call placement and call control.
To enter supervisor command mode, AT>Cn is entered, where
n is the port to control. AT>C? can be entered to display which
port is being controlled. To return to control of the DTE port
to which you are connected, enter AT>C0 or AT>C.
For example, a user may be connected to DTE port 3 and wants
to control DTE port 1. The user enters AT>C1 at the DTE
console. Now the user may operate as if he or she were
connected to DTE port 1. All port commands issued from here
on will affect DTE port 1 until the AT>C command is entered.
In supervisor command mode, when a call is placed for another
DTE port, the controlled port enters the on-line mode while the
supervisor port is still off-line. The supervisory port still has
full control of the controlled DTE port. Connect messages are
directed to the supervisor port in addition to the port being
controlled.
Caution: There is no mechanism to prevent a DTE port from
being controlled by another DTE port. A DTE port can be
controlled by more than one other DTE port.
UTA220/UTA220k
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