Specifications

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CSU/DSU MS DBU
DBU AND E THERNET C ARD S LOTS
CAUTION
Remove power from the unit prior to installing or removing modules.
The CSU/DSU MS DBU rear panel has two card slots for the installation of dial-
backup and Ethernet cards. To insert cards:
1. Remove power from the CSU/DSU MS DBU.
2. Slide the card into the corresponding rear slot until the card panel is flush
with the CSU/DSU MS DBU chassis.
3. Push card locks in (until they click) to secure the card and ensure proper
installation.
NOTE
Card slots are keyed to prevent improper installation.
T ELCO C ONNECTOR : N ETWORK I NTERFACE C ONNECTION
The CSU/DSU MS DBU has an 8-position modular jack labeled TELCO.
The telco connector is used for connecting to the DDS network.
The pinout for this connector is listed in Appendix A.
Each DBU module has a connector which is used for connection to the switched
backup network. The pinout for the connector depends on the card type.
Pinouts for 4-wire Switched 56, V.34, and ISDN 1B+D DBU options are shown
in Appendix A.
EIA-232 AND V.35 C ONNECTORS : DTE D ATA C ONNECTION /P RIMARY DTE
The primary DTE should be connected to either the EIA-232 DTE connector or
the V.35 DTE connector. The maximum cable lengths recommended are 50 feet
(15 m) for the EIA-232, and 100 feet (30 m) for the V.35. The pin assignments
for the connectors are listed in Appendix A.
The V.35 connector is recommended for use with data rates above 19.2 kbps.
The EIA-232 connector works up to 56 kbps with a low-capacitance cable or with
the external-transmit-clock option selected. The primary DTE rate is configured
from the front panel. The primary DTE equipment can operate in asynchronous
or synchronous modes.