2. When the radio is powered ON by turning the Power/Volume Switch to clockwise. When any
frequency programmed on Group #16 for Emergency alerting signal or for Priority channel, the
radio also receive the carrier wave on this frequency.
3. When the carrier wave is detected on one of the destined frequencies, the radio immediately stops
scanning to recognize the CTCSS and compares it with the radio’s preset CTCSS. If the CTCSS in
the received carrier wave coincides with the preset CTCSS of the radio, squelch is opened and the
radio is engaged in the Receive mode. If no CTCSS is detected, or if the detected CTCSS does not
coincide with the radio’s preset CTCSS, then the radio keeps on scanning the destined frequencies
between Group# and #16(Emergency).
Caution:
If the CTCSS is programmed “None”, the squelch can be opened for any carrier wave that
the radio receives.
4.
Monitor/Emergency button provides either of the following function. You need to select to assign
the function as Monitor or Emergency.
Monitor
….. Short pressing of Monitor/Emergency button By short pressing of Monitor/Emergency
button (less than 2 seconds), the radio opens the squelch and receives the carrier waves in
transmission on the channel where the scanning stops. This is to be used for checking whether the
channel is open or in use.
Emergency
….. Long pressing of Monitor/Emergency button by prolong pressing of
monitor/Emergency button (more than 2 seconds), the radio keeps on transmitting the Emergency
alerting signal until the Power Switch is turned OFF. The Emergency alerting signal can be selected
from 10 types of tones and duration/interval is also programmable.
Important:
While the Emergency alerting signal is being transmitted, the Mic line of SR390/450
radio is also in active, so that you can override your message over the alerting tone for letting a
Group member know of your location and emergency message. For facilitating this function, it is
important that the duration of alerting tone transmission should be programmed to hold sufficient
time for enabling to transmit the massage at the same time. While any one of the SR390/450 radio in
a Group is transmitting the Emergency alerting signal, all other radios in the same Group coinciding
the CTCSS are kept on capturing the signal (and message), and are unable to communicate with
others. For not blocking the Group’s communication, it is important that the interval of Emergency
alerting signal should be programmed to hold sufficient time for enabling other radios in a Group to
maintain the communication for the rescue order in the interval of
Emergency alerting tone. The default setting of signal interval is 5 seconds.
5. When PTT Button is pressed, or when the radio PTT is triggered by VOX, channel scanning is
immediately stopped and the operator can hear a short “Pip!” tone via his speaker of Headgear or
Ear Mic for letting him know that his transmission becomes established. If the existing carrier wave
from other transmission is detected in that frequency, no Ready-to-Tx tone as “Pip!” is heard, and
Tx status cannot be engaged. In this case, release the PTT Button for making the radio restart to scan
the channels, and press the PTT Button once again, or make voiced sound again after 0.7 second in
VOX mode, to catch the “open” channel.
Remarks:
Engaging the Tx status by neglecting the existence of other carrier wave in air can be
programmed.
6. When PTT Button is released, or when the radio is turned to Receive/Stand-by status by no
detection of voiced sounds to trigger the VOX, the Mic line is to be OFF and send the
End-of-Transmit signal for indicating to terminate transmission. When the Tx status is disengaged,
the operator can hear a short “Pip! Pip!” tone via a speaker of Headgear or Ear Mic for letting him
