RTS MCS-325, Manual

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2-9
resistor values. These resistors would normally be installed in the cable connector, but may be
placed at any point in the signal path. Recommended values are shown in Figure 2-4.
Program Inputs, J14 and J15
The PROGRAM A and B inputs accept line-level (0 dBu nominal), balanced audio. The program
inputs are connected using ¼-inch stereo phone plugs.
The MCE325 must be internally programmed to assign the program inputs to the intercom lines,
headphones, or speaker output (see “Program Assignment”). Program volume to the headphones
and speaker is controlled by the PGM VOL control on the front panel.
External Speaker, J27
The SPEAKER OUTPUT jack provides a bridging-type output for an external speaker (8 ohms
minimum). The external speaker is connected using a ¼-inch phone plug.
CAUTION
The MCE325 provides a bridging-type speaker output. DO NOT LET EITHER SPEAKER
LEAD CONTACT GROUND.
The external speaker is turned on and off by the front panel SPKR ON switch.
Auxiliary Connector, J22
Four-Wire Channel A and B Input
The four-wire channel A and channel B inputs are connected at the auxiliary connector as
follows:
The four-wire inputs must be assigned, using internal programming jumpers J19 and J20, before
they can be used (as previously described in “Intercom Line-Channel Configurations (DS1-DS3,
J6, J7, J19 & J20).”
Figure 2.5 Connectors J14 and J15.
SECTION FUNCTION
Tip Program high
Ring Program low
Sleeve Common
Figure 2.6 Connector J27.
SECTION FUNCTION
Tip Speaker plus
Ring Speaker minus
Sleeve No connection
Table 2.6 Auxiliary connector, J22.
PIN # FUNCTION
8 Four-wire channel A high
21 Four-wire channel A low
9 Four-wire channel B high
22 Four-wire channel B low