QTR-2/QTR-600 Wireless Portable
Audio Control Switch Modes
The QTR-2/QTR-600 portable has only two operating controls: a combined on/off and
headset volume control, and a push-button audio control switch. The function of this switch is
internally programmable to any of the following three modes:
1) Push-to-mute (transmitter remains “on;” audio is continuous until interrupted by
depressing the switch). This mode allows the user to cancel transmitted audio during a
cough or during a local conversation, while continuing to transmit an unmodulated
signal (to override weaker interfering signals that might be received at the master
station).
2) Push-to-enable (transmitter remains “on;” audio is disabled until the switch is
depressed).
3) Push-to-talk (transmitter and audio are both “off” until the switch is depressed). This
mode allows simplex communications between an unlimited number of portables,
without a master station.
The use of the push-to-talk mode is discouraged for normal applications due to the
high-sensitivity of the system receivers and the possibility of weak interfering signals
being received (which often results in very noisy system output).
Typical sources of interfering signals include: spurious outputs from poorly adjusted
two-way radio transmitters; harmonic output from FM radio transmitters; radiated
harmonic energy from clock signals in computers and other digital equipment; leakage
from CATV and MATV systems; and inadequately shielded RF test equipment.
6
Q PLUS
Intercom
Interface
S1
S2
S3
S4
S5
1
2
3
4
5
6
7
8
9 10 1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Clear-Com*
X
X
X
X
X
X
X
X
Clear-Com
(Dry)*
X
X
X
X
X
X
X
X
Clear-Com
TW*
X
X
X
X
X
X
X
X
X
X
RTS*
X
X
X
X
X
X
X
X
X
X
RTS (Dry)*
X
X
X
X
X
X
X
X
X
X
Telex*
X
X
X
X
X
X
X
X
X
X
X
X
X
4-Wire
X
X
X
X
X
X
X
X
X
X
Carbon Mic
2-Wire**
X
X
X
X
X
X
X
X
X
X
X
X
X
Carbon Mic
3-Wire**
X
X
X
X
X
X
X
X
X
X
X
X
Table 1. QX-6A/QX-600 master station switch settings for standard intercom systems. NOTE: “X”
designates switch is “ON”; a “blank” designates switch is “OFF”.
*Turn master station headset “SIDETONE” control (R166) to minimum.
**NOTE: Carbon-mic systems vary widely in technical implementation. If these settings do not
work properly, consult the Vega factory.
