ADTRAN DSU IV ESP, User Manual

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Chapter 1. Introduction
1-6 DSU IV ESP User Manual 61204011L1-1
ESP Dial Backup Options
4-Wire Switched 56 Card
The dial-up 4-wire SW56 DBU card (P/N 1204001L1) allows
customers to pay for actual usage of the data connection when the
unit is active. The regional operating companies provide 4-wire
local loop service to SW56 customers. This card supports DTE rates
of 2.4, 4.8, 9.6, 19.2, 38.4 (asynchronous or synchronous), and 56
kbps (synchronous). An additional DTE rate of 57.6 kbps is
available in async modes.
V.34 Card
The V.34 DBU card (P/N 1204002L2) supports V.32 bis modem
modes of operation, V.34, and V.FC modes. The V.34 option runs
synchronous rates up to 33.6 kbps, and the V.32 operates up to 14.4
kbps. Asynchronous mode provides the throughput of 57.6 kbps
and is less dependent on data types.
ISDN Card
The 1B+D Basic Rate ISDN DBU card (P/N 1204004L1) provides
the customer a backup switched 56/64 kbps ISDN circuit.
Synchronous and asynchronous DTE rates of 2.4, 4.8, 9.6, 19.2, and
38.4 kbps per CCITT V.120 are also supported. An additional DTE
rate of 57.6 kbps is available in async mode and is compatible with
the 4-wire SW56 DBU card.
The BRI DBU card (P/N 1204004L1) provides a full 2B+D BRI ISDN
service when installed in the TSU ESP or TSU IQ but only provides a one
64K bearer channel (1B+D) when installed in the DSU IV ESP.