AT Command Operation
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.
COMMAND SCOPE
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
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).
Supervisor Command Mode
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
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 |
