Technician Troubleshooting Guide
Model 478 (D-15)
2
Figure 1. Operating Controls
Key
Control Name
Function
1
Power Switch
Controls application of power to the system.
Power Indicator Light
Indicates power is applied to the system.
2
Volume Control
Adjusts the internal speaker (listen) audio level.
3
Standby Touch Switch
Silences intercom audio to eliminate pickup of undesired
background noise and reconnects optional music/message
source to the external speaker when unit is not in use. The
system automatically exits the standby mode with vehicle
detection or when the Touch/Talk switch is pressed.
4
Touch/Talk Switch
Controls talk/listen communications. Operator touches switch
to talk and cancel alert tone. Operator releases switch to
listen.
5
Indicator Lights
Red indicates TALK mode.
Green indicates LISTEN mode.
Yellow indicates vehicle presence.
Yellow light above STANDBY lights and all other lights are
extinguished when the system is placed in the standby mode.
