Northern Airborne Technology NPX138 - Manual (Page 46)

NPX138 Panel Mount Radio Manual SM41 Rev. 4.00
• SCAN
There are three scanning modes available for selection: LIST, PRIORITY, and
LIST+PRI. See section 3.10 for further details on scanning.
• P1
This is the Priority channel used in Priority and List+Priority Scanning. It can be set
to any valid channel number, or if not required, can be set to NONE. When the
SCAN option is selected to LIST, the priority channels are not active but are retained
in memory. See section 3.10 for further details on scanning.
• PWR-UP HELP
The display of the HELP screen at power up can be selected on or off.
• PWR-UP CHAN
This is the channel the radio will go to when powered up. The operator can select a
specific channel or set this option to PDC (Power-Down Channel). PDC will cause
the radio to power up on the last used channel.
3.9 Tones
3.9.1 General
The tone system used by the NPX radio is a Continuous Tone-Coded Squelch System
(CTCSS), as defined by an Electronic Industries Association (EIA) standard. The radio
adds these tones to the normal signal modulation (such as voice) to uniquely identify or
select a particular radio or group of users.
More commonly, these tones are referred to as sub-audible tones. This is because the
filtering action of the radio eliminates them from the received audio. Therefore neither
the sending nor receiving party will hear them. These tones are also sometimes
referred to as Private Line (PL) tones.
Page 3-12 Nov 10, 2003
ENG-FORM: 806-0105.DOT
Amendment # 4 Jun 1 0, 2005
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.