PS-SAU-1900E
Mar. 8
th
,1999 (Rev. 0.0)
--- CONFIDENTIAL AND PROPRIETARY ---
29
Cancel Call Forwarding:
Call Forward is canceled when the LAU user sends the
appropriate cancellation code to the B/S.
Message Waiting (Stutter Dial Tone):
Implementation of this feature is provided through either
the FLASH_WITH_INFORMATION message or
FEATURE_NOTIFICATION message
.
Upon receipt of the
appropriate information from the B/S, the LAU will apply a
suitable stuttered dial tone when an off hook condition is
detected on the analog loop interface. In addition, an
appropriate CLID format Message Waiting indication will be
provided to activate the Message Waiting indicator on any
attached CLID device.
3.1.6. Special
Notes.
There are certain special conditions which are considered in the software operation, and are defined
below.
•
The “Glare” Condition:
The LAU must provide dial tone to an external telephone immediately
when an off hook condition is detected, as long as a valid PILOT channel is present. However, this
means that a user could be in the process of dialing a call when a call comes in from the network,
because the network is not aware of the off hook condition.
The LAU handles the “glare” situation as follows:
1. The incoming call will cause the LAU to apply a Call Waiting tone to the analog loop interface.
2. When the Call Waiting tone is received by the user, two options exist. In the first option, the
user may connect immediately to the incoming call by flashing the loop interface. When the
flash is received, the LAU will establish the voice path to the incoming call. The second option
is for the user to hang up the handset. In that case, the LAU will apply ring signal to the analog
loop, and the voice path will be established when the handset is lifted.
3. If the far end disconnects before the voice path is established (via the above process), then dial
tone is returned to the loop interface, and digit collection begins again from the first entered
digit
In either case, the LAU will discontinue the process of collecting dialed digits if an incoming call
indication is received prior to sending the dialed digits to the B/S.
3.1.7. Emergency
Numbers.
The product will accept certain three digit emergency numbers and will send them without waiting for any
special termination or SEND operation.
Also System provider can set
Emergency Call Hold
information to prevent terminate the call by
subscriber if the call is Emergency call.
3.2. Hardware
Interfaces.
The following sections detail the general requirements of the LAU’s hardware / software interface.
