Specifications

Operating Modes
2-13
• DDS Down - DDS goes down due to Out of Service codes, Abnormal Station
codes, loss of multiport framing, or loss of network framing for a user-selectable
time period.
• No Signal - an invalid DDS signal is received from the network.
• Network Down - the DAP dials after the DDS network goes down or an invalid
signal is received from the network.
• DTR - the DAP dials when the DTR signal is active. This setting allows external
routers and FRADs to originate dial backup calls.
Note: The DAP will not automatically dial when it is in a test state such as Channel
Network Loops.
You may select any DAP in the network (remote or central) for automatic dialing. Both
DAPs can answer a call, but only one should be configured to automatically originate the
call.
Front Panel Status Information
When the ISDN IDBU and the network have synchronized and completed the activation
process and the D-channel is ready to exchange control messages, the following status
information is displayed on the front panel while the dial-up connection is being
established (through any of the methods):
• A dial backup connection is being established.
• When calls have been successfully connected.
• Whether the dial line is connected or disconnected.
• Call progress information (ringing, busy).
Call Establishment
When the dial backup connection is initiated and automatic dial is enabled on the
originating DAP, the answering DAP's primary telephone number is dialed. When
automatic dial is disabled, you may manually dial the DAP's primary or any of its four
alternate telephone numbers.
Call Answering
When automatic call answering is enabled, the DAP answers incoming dial line calls in
response to one of the following user-selectable conditions: