RAC 104 • Installation and Operation 2-7
3
RS-232 connector — Plug an optional RS-232 device into this
3-pole captive screw connector. Wire the connector as shown
below.
Transmit (Tx)
Receive (Rx)
Ground (Gnd, )
RS-232
Tx Rx
Pin
RS-232 function Description
1 Tx Transmit data
2 Rx Receive data
3 Gnd Signal ground
4
Line level selector DIP switches — Set these switches to
-10 dBV (unbalanced, consumer line level) or +4 dBu (balanced,
professional line level). There are four switches, one for each
input group and output group.
ON
LINE LEVEL
IN
A B A B
OUT
+4 dBu
-10 dBV
5
Power connector — An external 12 V power supply is included
with the unit. Plug it into this 2-pole captive screw connector.
Wire the connector as shown below.
Orange Captive Screw
Connector
Tie Wrap
Power Supply
Output Cord
Ridges
Smooth
AA
SECTION A–A
CAUTION
When connecting the power supply, voltage
polarity is extremely important. Applying power
with incorrect voltage polarity could damage the
power supply and the RAC 104. Identify the power
cord negative (ground) lead by the ridges on the
side of the cord or a black heat shrink wrapping
around it.
The two power cord wires must be kept separate
while the power supply is plugged in. Remove
power before wiring.
To verify the polarity before connection, check the no load
power supply output with a voltmeter.
