3
PRIMARY UNITS:
The “C” models default to Primary, or
speaker
, mode. In Primary mode, the unit acts as
a speaker and broadcasts audio signals generated elsewhere in the intercom system.
Depressing the Talk switch turns the unit into a microphone and enables the user to
broadcast to all other intercoms in the system. Releasing the switch returns the unit to
Primary mode. Figure 4 on page 10 illustrates a Primary/Secondary intercom system.
SECONDARY UNITS:
The “D” models default to Secondary, or
microphone
, mode. In Secondary mode, the
unit is designed to serve as a hands‑free microphone with transmission to all Primary
units in the intercom system. The Secondary unit will act as a speaker and broadcast
audio transmissions only when the Talk switch of any Primary unit in the intercom
system is depressed. Figure 4 on page 10 illustrates a Primary/ Secondary intercom
system.
CALL BUTTON:
The “A” models are equipped with a Call switch. Depressing the call switch transmits an
890 Hz tone to all units in the intercom system.
The call signal is louder than normal voice messages being carried on the line.
Do not depress the call switch while carrying on a conversation with someone on the
system. This will subject the listener to very loud sound levels.
The volume of the call signal is affected by the volume control on the receiving unit, so if
volume is turned all the way down at a receiving station, the call signal will not be heard.
MICROPHONE:
The “‑7” Hand‑Held Noise Cancelling Microphones are recommended for use in
environments with high levels of ambient noise. Keying the microphone overrides the
default mode of the intercom and enables audio transmission to all Primary units in
the intercom system. Figure 2 on page 8 illustrates a common intercom system where
hand‑held microphones are used.
Additional Model Information
Letter Group
Function/Feature
“A”
Call button
“C”
Primary mode
“D”
Secondary mode
Number Group
“‑1”
Remote power
“‑2”
Provisions for external talk/listen switch (foot pedal ready)
“‑3”
External call contacts for auxiliary signal
“‑4”
Extreme temperature use (‑50 °F to 150 °F)
“‑6”
Designed for use in a zoned system
“‑7”
Provisions for hand‑held noise canceling microphone
“‑8”
Additional pre‑amp for use with remote Secondary speaker
Miscellaneous
“‑M22”
Equipped with remote monitor switch
“‑M34”
Provisions for headset microphone with belt switch
“‑M44”
Remote speaker volume control
Table 2
