COMSPHERE 3900 Series Modems
5-38 September 1998 3910-A2-GN32-40
Table 5-5
(6 of 6)
Leased Line Configuration Options
Lease_Lookback: Disable
Nxt Disable Enable
Lease Lookback. While operating on backup lines, this configuration option allows the modem to test the
primary 4-wire leased lines for connectivity by detecting line energy across the normal line bandwidth. This
test of the primary lines will not interrupt the data flow on the backup lines. The configuration option settings
must be the same at both ends.
Dual_Leased_Ln: Disable
Nxt Disable Enable
This configuration option is only available when the Dual Leased Line device option is installed.
Dual Leased Line. Allows the 2-wire backup facility to function as a 2-wire leased-line facility. When this
configuration option is disabled, the backup facility is a 2-wire dial line.
NOTE:Plug the leased line into the jack labeled DIAL on the rear panel of the modem. Except for dialing,
ring indication, and call progression functions, you control the backup function as if it were a normal
dial backup.
NOTE:Once the Dual_Leased_Ln configuration option is enabled, the Bakup_TXClk_Src configuration
option can be enabled.
BackupLineCheck: Disable
Nxt Disable Enable
This configuration option is only available when the Dual Leased Line device option is installed.
Backup Line Check. Tests the backup circuit for availability while the modem is operating on the primary
leased lines. The test involves detecting line energy across the normal bandwidth. This test of the backup
lines will not interrupt the data flow on the primary lines. The configuration option settings must be the same
at both ends.
NOTE:In network applications where the modem is in backup mode and is connected to a modem other
than the modem connected to the primary leased-line, enabling this configuration option can cause
problems.
V.42/MNP/Buffer
V.42/MNP/Buffer configuration options determine the type of error correction and flow control
used by the modems and attached DTEs.
Some choices within this group may not appear depending upon how previous configuration
options have been selected. If the Async/Sync Mode configuration option is set for
synchronous operation (refer to the DTE Interface configuration options group), then the
V.42/MNP/Buffer group does not appear on the LCD. Any changes made to configuration
options within this group only take effect after a disconnect.
Table 5-6 shows each V.42/MNP/Buffer configuration option as it appears on the LCD, with the
Async Dial factory default setting shown following the colon ( : ) on the first line and with all
available selections listed on the second line. Following this is a description of the configuration
option. Factory default settings are listed in Appendix F.