61200305L2-1B © 2004 ADTRAN, Inc. 353CFG-1 Dial Backup for Dedicated T1 CircuitsIntroductionDial backup (DBU) is an ATLAS 550 capability which allows you to create alternate data connections inthe unit to ensure data integrity in the event of a primary circuit failure. This note explains what dialbackup is and how to configure an ATLAS 550 to support it. There are three steps to configuring theATLAS 550 for dial backup:1. Configure the Dedicated T1 Data Link2. Configure the Dial Backup PRI3. Configure the Dial Backup EndpointBefore You BeginThis 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.DescriptionThe ATLAS 550 will either originate or answer a dial backup call upon detection of a network failure ordata failure on the T1/E1. A network failure is any physical layer T1/E1 failure, such as red alarm or lossof signal (LOS). A data failure is detected when the ATLAS 550 no longer receives keep-alive responsesover the 8K inband channel. The data criteria for dial backup can only be used when configured to monitorthe inband channel.The primary link to be backed up must be a data link to a V.35 port. Dedicated dial backupfor T1 ports is not currently supported.
