Motorola MCS 2000 User Manual page 105

Non-XL Scan Unsquelch
Duration (ms)
XL Scan Unsquelch Duration
(ms)
Secure Punch Thru
Use the UP/DOWN arrow keys to select the Non-XL Scan Unsquelch
Duration. When scanning for coded transmissions, this field
determines the period of time that the radio will wait for a Non-XL
(Cipher Feedback) encrypted signal to be detected following a Carrier
Detect. The valid range is 0 (zero) to 6375 ms in 25-ms increments.
The default is 275 ms.
Use the UP/DOWN arrow keys to select the XL Scan Unsquelch
Duration. When scanning for coded transmissions, this field
determines the period of time the radio will wait for a Non-XL (Cipher
Feedback) or XL encrypted signal to be detected following a carrier
detect. The range is 0 (zero) to 6375 in 25-ms increments.
The default is 875 ms.
Use UP/DOWN arrow keys to scroll or directly enter the desired value.
The RSS allows the user to set the Secure Punch Thru feature to one of
the following settings: Disabled, Always On, or Variable Volume
Position (that is, the feature will become active when the volume knob
is set to a level greater than this programmed volume position).
The valid range of the variable volume position is 1 to 254. (The latter
figure corresponds to the absolute position of the radio volume knob.)
SECURE Punch Thru is a feature intended to reduce high volume
distortion in the SECURE receive mode by removing much of the
distortion-producing low frequency content (from amplifier clipping
and speaker/housing overload), and improve intelligibility in high
background noise environments (when the radio is at high volume),
by boosting the high frequency content that tends to get washed out
in such conditions.
The SECURE Punch Thru feature is activated when the radio is
receiving in the SECURE mode and the volume knob is beyond an RSS
programmable position. The feature turns off the de-emphasis filter in
the receive SECURE audio path, leaving the audio pre-emphasized
from the transmitter (that is, the lower frequencies are reduced and the
higher frequencies are increased).
Note that this feature requires the transmitting radios to use pre-
emphasis, which is normally the case. Also, the Secure Punch Thru
feature activation point can be anywhere from the volume knob's
lowest position (turned on all the time when receiving SECURE) to its
highest position (turned off all the time when receiving SECURE).
The default is Disabled.
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