61200305L1-1F © 2002 ADTRAN, Inc. 365
DIAL BACKUP FOR DEDICATED T1 CIRCUITS
Introduction
Dial backup is an ATLAS 550 capability which allows you to create alternate data connections in the unit
to ensure data integrity in the event of a primary circuit failure. This note will explain what dial backup is
and how to configure an ATLAS 550 to support it. There are three steps to configuring the ATLAS 550 for
dial backup: Configuring the Dedicated T1 Data Link, Configuring the Dial Backup PRI, and Configuring
the Dial Backup Endpoint.
Before You Begin
This application requires an ATLAS 550 containing firmware B.01 or later, a V.35 Nx Module
(P/N 1200311L1), and a BONDing Module (P/N 1200326L1) if bonding of B channels is required.
Description
The ATLAS 550 will either originate or answer a dial backup call upon detection of a network failure or
data failure on the T1/E1. A network failure is any physical layer T1/E1 failure, such as red alarm or loss
of signal (LOS). A data failure is detected when the ATLAS 550 no longer receives keep-alive responses
over the 8K inband channel. The data criteria for dial backup can only be used when configured to monitor
the inband channel.
The primary link to be backed up must be a data link to a V.35 port. Dedicated dial
backup for T1 ports is not currently supported.