User guide

Installation 2-11
2
To connect the DSU/CSU to the DTE devices, you use a data port interface cable. The
cable type depends on the DSU/CSUÕs interface (V.35 or RS-449) and its operating
mode (DCE or DTE). Table 2-1 lists the cable and distance requirements.
Fireberd Compatibility and V.35 Cable
If youÕre using a DTE cable not supplied by Digital Link when connecting a Fireberd
test set to a DSU/CSU conÞgured for V.35, make sure the following pins are not
connected on the cableÕs V.35 end:
¥ BB, Z, EE, CC
These pins are reserved for special functions in the Fireberd test set.
Table 2-1 Connecting the DTE cable
DSC/CSU Cable
In
DCE mode Use a DTE cable.
For most applications, the customer equipment operates as a
DTE. Set
the
DSU/CSU operating mode as DCE.
In DTE mode Use a DCE cable.
In some instances, as in tail circuit applications, the customer equipment
operates as a
DCE. For these applications, set the operating mode as
DTE. See ÒMODEÓ and ÒFORMATÓ <cell>on page 3-22.
V.35 interface Use the cableÕs V.35 connector to connect to the DTE device and the DB-
25
connector to connect to the DSU/CSU.
RS-449 interface Use the cableÕs RS-449 connector to connect to the DTE device and the
DB-25
connector to connect to the DSU/CSU.
Distance Maximum distance between the terminal and
DSU/CSUÑ50 ft.
NOTE: For EIA 530 or X.21 applications, use an EIA 530 or X.21 cable and set the
format to RS-449.