3M 478DA (D-15) - Manual (Page 10)

Technician Troubleshooting Guide Model 479 (D-30)
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SP-208A
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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 mainstation internal speaker (listen) audio level.
3 Talk Switches (A & B) Control talk/listen communication for the respective channel
(A or B). Operator touches switch to talk and releases switch
to listen.
4 Standby Switch Silences audio to eliminate pickup of undesired background
noise when unit is not in use. Touching either the Channel A
or Channel B Talk Switch releases STANDBY mode.
Vehicle Detection automatically places the system into the
Channel A listen mode.
5 Indicator Lights (same for Channel A and
Channel B) Red indicates TALK mode.
Green indicates LISTEN mode.
Yellow indicates vehicle presence (when used with 3M
SODAR or magnetic loop detection system).
All indicator lights are extinguished when mainstation is in
the standby mode.
6 Standby Mode Switch AUTO (automatic) position causes system to switch from
Channel A Listen to Standby when there is no vehicle detect
signal. MAN (manual) position allows operator to use
Channel A without vehicle detection.