Technical data

74
By default, the Dialogic
®
Diva
®
TTY interface operates in "channel pool" mode. It presents the available Dialogic
®
Diva
®
Media Boards as one board to the user application. This board owns the channels provided by the real
Diva Media Boards.
This feature hides the call distribution details from the application and allows creation of servers such as RAS.
You can use the AT+iQ command to control this behavior and to bind specific Diva TTY interfaces to specific Diva
Media Boards. See AT-command set on page 49 for more information.
Note: It is possible to bind specific Dialogic
®
Diva
®
TTY interfaces to specific Dialogic
®
Diva
®
Media Boards. But it
is not possible to bind specific Diva TTY interfaces to specific B-channel numbers due to the fact that B-channel
resources are automatically assigned by the active signaling protocol.
Handling of incoming calls
Incoming calls are handled in the following sequence of operations:
1. The Dialogic
®
Diva
®
Media Board receives a call.
2. The Diva Media Board uses the active signaling protocol to select the B-channel that will be used for this call.
3. The Diva Media Board delivers the call to the Dialogic
®
Diva
®
TTY driver.
4. The Diva TTY driver delivers the call to the first application that matches the call type and is ready to receive
incoming calls (ATS). See AT-command set on page 49 for more information on the ATS commands.
Handling of outgoing calls
Outgoing calls are handled in the following sequence of operations:
1. The user application issues a call on an arbitrary Dialogic
®
Diva
®
TTY interface.
2. The Diva TTY interface transfers the call request to the first Dialogic
®
Diva
®
Media Board that is able to
handle this call type and owns free B-channel resources.
3. The Diva Media Board uses the active signaling protocol to select the B-channel that will be used for this call.
The ESCAPE sequence enables you to switch from ONLINE mode (data transfer mode) to ESCAPE mode
(command mode with the connection established in the background).
The ESCAPE sequence includes the following procedure:
1. No data is sent to TTY for 2 seconds.
TTY "channel pool" mode
"ESCAPE" sequence (+++)