12
T1/E1 FIBEROPTIC LINE DRIVER
3.4 Setting the Switches
WARNING
Disconnect the unit from the power line before removing cover.
HIGH VOLTAGE—Any adjustment, maintenance, and repair of the
opened instrument under voltage should be avoided as much as
possible and should be carried out only by a skilled person who is
aware of the hazard involved.
Capacitors inside the instrument may still be charged even after the
instrument has been disconnected from its source of supply.
To change the switch settings, follow these steps:
1. Disconnect the power cable from the mains outlet.
2. Gain access to the Line Driver interior. Release the two rear panel screws
and use them as levers to pull out the interior of the unit as a drawer.
3. Identify the switches, according to Figure 3-1.
4. Install the switches in the desired positions (refer to
Section 3.5
).
5. Reinstall the Line Driver drawer.
3.4.1 I
NTERNAL
S
WITCH
S
ETTINGS
I
NFORMATION
Before installing the Line Driver, set the internal switches according to your
application (that is, electrical interface and optical link characteristics). The
switches are located on the Line Driver board, as shown in
Figure 3-1
. Switch
functions are also listed in
Table 3-2
.
3.4.2 I
NTERFACE
J
UMPER
The interface jumper (item 4 in
Figure 3-1
) selects one of three interface options:
• 100 (for T1 balanced signals, usually applied by the DB15 connector).
• 120 (for E1 balanced signals, usually applied by the DB15 connector).
• 75 (for E1 unbalanced signals, usually applied by the two BNC connectors).
