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Located on the rear panel of the DS3 Backup I/O are six bnc connectors. The connectors are laid out in Tx/Rx pairs. There are six Tx/Rx pairs so the DS3 Backup I/O can be a backup for each of the Primary DS3 units in the network. Once one of the primary nodes fails the Tx/Rx BNC pair on the rear of the backup unit will take over. Any calls that are in process will be lost. See IMG 1010 - N plus 1 DS3 Overview for more information on setting up the N+1 network.
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A DS3 line (also known as a T-3) is an ultra high-speed connection capable of transmitting data at rates up to 45 Mbps. A DS3 line is equal to approximately 672 regular voice-grade telephone lines and supports a DS3 signaling interface which is bipolar with Bit 3 Zero Substitution (B3ZS). The DS3 interface is a 75 ohm coax cable and must be made with true 75 ohm cable and connectors. The DS3 interface supports either T1 or E1 protocol but not both on same Physical IMG 1010. Support for either T1 or E1 Protocol is based on the value of the Host Flag setting in the dhcpd.conf file. See IMG 1010 - Setting Host Flags for more information on setting host flags.
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