PS-SAU-1900E
Mar. 8
th
,1999 (Rev. 0.0)
--- CONFIDENTIAL AND PROPRIETARY ---
28
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B/S Call Termination event:
A Disconnect message is received from the B/S. In this case, the
LAU performs necessary house-keeping, then disconnects from the TALK state. If the user remains
off hook, then dial tone is returned. Otherwise, the LAU returns to the IDLE state.
•
System Lost event:
A System Lost condition occurs. In this case, the LAU applies the appropriate
tone to the analog interface.
3.1.5.
VERTICAL FEATURES Interactions.
The LAU supports several network vertical features. General implementation guidelines are defined
below.
Calling Line Identification:
This feature is defined in a previous section.
Call Waiting:
Call Waiting is a network feature which permits the LAU
user to access incoming calls without terminating the
current call. The presence of an incoming call is signaled
to the LAU by the B/S by application of a special audio tone
over the voice path. Upon receipt of this tone, the LAU
user has the option of accepting the incoming call, or
ignoring it. If ignored, no further action occurs. To accept
the incoming call, the user applies a hook flash to the
analog loop interface. This flash is detected by the LAU,
which then transmits a FLASH_WITH_INFORMATION
message to the B/S. The B/S places the current call on
hold, then connects the incoming call. The LAU user
returns to the held call be generating a second hook flash.
Three Way Calling:
Three Way Calling (3WC) is initiated by the LAU user while
connected in the Conversation state with another party.
The feature is initiated when the LAU user applies a
hookflash to the analog loop interface. The LAU transmits
a FLASH_WITH_INFORMATION message tot he B/S,
which then responds by placing the current call on hold. It
then applies dial tone to the voice path. The LAU user
responds by dialing the third party’s number, terminated by
another hook flash. The terminating hook flash causes the
LAU to transmit the received digits to the B/S, which then
connects the second party. The LAU user connects the
first party by applying a third hook flash to the analog loop.
The second party is disconnected when the LAU user
sends a hook flash after the three parties have been
connected.
Call Forwarding:
Call Forward is initiated when the LAU user takes the
analog loop off hook and dials the appropriate initiating
DTMF code, followed by the number to be forwarded to,
then terminated by the appropriate termination sequence
(either “#” or Autosend). The B/S responds with a
confirmation tone.
