HTX-212 Two-Meter Mobile Transceiver
(190-1125)            Understanding the HTX-212       Faxback Doc. # 19438

DUAL VFO MODES

The VFO (Variable-Frequency Oscillator) modes let you directly select a
frequency anywhere within the HTX-212's operating range.  Your HTX-212 
has two VFOs:  VFO-A and VFO-B.  You typically use the VFOs to tune to
frequencies you have not stored into one of the HTX-212's memory channels
(see "Memory Channels," below).

A related feature of the HTX-212 lets you transmit on the frequency 
selected with one VFO and receive on the frequency selected with the other
VFO.  (See "Using the Dual VFOs for Duplex Operation," Faxback Doc.#     ,
Advanced Operation.

DTMF (TOUCH-TONE) FEATURES

DTMF (Dual-Tone, Multiple Frequency) is another term for touch-tones (the
tones a telephone produces when you press a digit).  This standard set of
tones is used by many different amateur radio systems for accessing
programmable features and dialing through autopatches.

Your HTX-212 produces all 16 standard DTMF tones (0-9, *, #, A, B, C, and
D).  It has six DTMF memories which can each hold up to 15 digits for quick
transmission.  You can also set the HTX-212 to listen for a specific set of
DTMF tones, and alert you when it detects them (this feature is called
DTMF Paging).  Until it hears the sequence, the HTX-212 does not pass any
transmissions to the speaker.

Group Calling lets you DTMF page a single person or an entire group of 
people.  To use group calling, every person in the group selects the same
first three digits as their DTMF page sequence.  They then select up to
four additional digits unique to each person.  To page an individual, you
transmit their entire DTMF page sequence.  To page the entire group, you
transmit at least the first three digits of the sequence, followed by the
DTMF tones for A, B, and C.

NOTE:  Group Calling only works with the HTX-212 and other transceivers
       that support this feature.

SUBAUDIBLE TONE (CTCSS) FEATURES

Subaudible tones, also know as CTCSS (Continuous Tone-Coded Squelch System)
are low-frequency tones that are mixed with a transmission.  They are used
by many repeaters to limit interference from other nearby radio 
transmitters.  When a repeater uses a subaudible tone, it does not react to
any transmission that does not include that tone.

Your HTX-212 includes all 38 standard subaudible tones.  You can set your
HTX-212 to include any of these tones with your transmissions.  You can
also set your HTX-212 to limit reception to only those transmissions that
include the selected tone.

REPEATER OPERATION

Operation through a repeater, where you transmit on one frequency and
receive on another, is called duplex operation.  Operation direct to
another station where you transmit and receive on the same frequency is
called simplex operation.

A repeater is a station that receives a signal on one frequency (the input
frequency) and then retransmits that signal on a different frequency (the
output frequency).  Repeater antennas are typically located at the tops of
tall buildings or on antenna towers, so a relatively low-power signal can 
reach the repeater.  The repeater retransmits the signal at a high power.
This gives users of low-power transceivers the ability to communicate over
a much greater range.

To use a repeater, you must know the repeater's input and output 
frequencies.  Repeaters are usually identified by the output frequency.
Thus, a repeater that has an output frequency 146.94 is referred to as the
146.94 repeater.  To determine the input frequency you must know the
frequency offset (600 kHz for the 2-meter band) and the offset direction
(+ if you add 600 kHz to the output or - if you subtract 600 kHz from
the output).

Your HTX-212 is programmed with the default 600 kHz frequency offset and
direction for the 2-meter band.  When you tune a frequency that is normally
assigned for repeater use, the HTX-212 automatically selects the correct
input frequency.  See "Frequency Offset Defaults," Faxback Doc.# 19131,
Advanced Operation.

MEMORY CHANNELS

Your HTX-212 has 31 memory channels (30 standard memory channels and one
calling-frequency memory channel).  Each memory channel can hold a transmit
and receive frequency, subaudible transmit and receive tones, the transmit
power level, and whether subaudible tone transmit and squelch are on or
off.  You cannot store non-amateur frequencies in memory.

UNDERSTANDING THE DISPLAY

One or more of the following indicators appear when you turn on and use
your HTX-212.

VFO-A or VFO-B - appears when you select one of the VFO modes.  See "Dual
                 VFO Modes," above.

VFO-A-T
VFO-B - appears when you select the DUP-A mode (transmit on VFO-A and
        receive on VFO-B).  See "Using the Dual VFOs for Duplex 
        Operation," Faxback Doc.#    ,Advanced Operation.

VFO-A
VFO-B-T - appears when you select the DUP-B mode (receive on VFO-A and 
          transmits on VFO-B).  See "Using the Dual VFOs for Duplex
          Operation," Advanced Operation.

HIGH or LOW - indicates the transmit power level.  See "Setting the Power
              Level," Faxback Doc.# 15169, Basic Operation.

FUNC - appears after you press F.  Flashes after you Hold F for at least 1
       second.

LOCK - appears when you lock the HTX-212'S functions.  See "Locking the
       Controls," Faxback Doc.# 15169, Basic Operation.

T - appears when transmit subaudible tone is turned on.  See "Using 
    Subaudible Tone," Faxback Doc.# 19133, Using DTMF and Subaudible Tones.

T-SQL - appears when both transmit subaudible tone and subaudible tone
        squelch are turned on.  See "Using Subaudible Tones," Faxback Doc.#
        19133, Using DTMF and Subaudible Tones.

ALT - appears when you turn on the DTMF page/subaudible tone alert.  See
      "Setting the DTMF Page and Subaudible Tone Alert," Faxback Doc.
      # 19133, Using DTMF and Subaudible Tones.

+ or -  - indicates the duplex offset direction.  See "Overriding the 
          Duplex Offset," Faxback Doc. # 19131, Advanced Operation.

DTMF - appears when you turn on DTMF squelch.  See "Using DTMF Page," 
       Faxback Doc.# 19133, "Using DTMF and Subaudible Tones.

BUSY - appears when the HTX-212 is receiving a transmission.  See
       "Receiving Transmissions," Faxback Doc.# 15169, Basic Operation.

ON-AIR - appears when you transmit.

ALARM SYMBOL - appears when you turn on the Channel 1 alarm.  Flashes when
    (a bell)   there is a transmission on Memory Channel 1 and the alarm is
               turned on.  See "Checking Priority Channel 1," Faxback Doc. 
               # 19134, Using Memory Channels.

M-CH - appears when you tune to a memory channel.  See "Using the Standard
       Memory Channels," Faxback Doc.# 19134, Using Memory Channels.


(CS 2/14/96)

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