Maas AHT-28-V User manual

Thank you very much for using our two way radio.
This radio of modern design is reasonable structure
with stable functions. It is designed to meet different
customers' need for high quality with easy operation
and perfect capablity. We believe you are pleased with
its nice shape and excellent performance.
This manual is suitable for using the model of
AHT-28-V/AHT-78-U.
Maas
AHT-28-V/AHT-78-U
Handheld Transceivers
User’s Manual

www.maas-elektronik.com
Single band, dual display, dual standby
A/B band independent operation
2x128 channels storage and scanning
FM radio and 25 stations memory
Wide/Narrow band selectable
VOX 0~9 grade setting
Chinese/English voice prompt
CTCSS/DCS and scanning
1750Hz tone
ANI function
Shortcut menu operation mode
Emergency alert
DTMF and remote stun/kill/activate (optional)
8 groups of scrambler, 2/5 tone, remote stun/
kill/activate (optional)
Main Functions
Welcome to use two-way radio
www.maas-elektronik.com

www.maas-elektronik.com
Single band, dual display, dual standby
A/B band independent operation
2x128 channels storage and scanning
FM radio and 25 stations memory
Wide/Narrow band selectable
VOX 0~9 grade setting
Chinese/English voice prompt
CTCSS/DCS and scanning
1750Hz tone
ANI function
Shortcut menu operation mode
Emergency alert
DTMF and remote stun/kill/activate (optional)
8 groups of scrambler, 2/5 tone, remote stun/
kill/activate (optional)
Main Functions
Welcome to use two-way radio
www.maas-elektronik.com

CONTENTS
USING TIPS
UNPACKING AND CHECKING EQUIPMENT
Supplied Items
CHARGING BATTERY PACK
Charging Preparation
Charging Operation
INSTALLATION OF ACCESSORIES
Installation of Battery Pack
Antenna Installation
Installing Belt Clip
Installing External Micro/Speaker
Wrist Strap Installation
GETTING FAMILIAR
Radio Illustration
LCD Display
Keypad Functions
MODEL VERSION
WORKING MODE
Frequency Mode (VFO)
Frequency-Channel Mode (MR)
Channel Mode (CH)
FM Radio Mode
MENU Mode
Reset Mode
SET MENU MODE
SHORTCUT MENU OPERATION
DETAILED FUNCTION DESCRIPTION
Scan & Scan Mode setting
Priority Transmit
VOX Level & VOX Switch
TX Power setting
Squelch Adjustment
Dual Wait/Standby
LED Display Mode
Background Light Color
Keypad Beeper setting
Automatic Number Identity
Transmitter Time-Out Timer
Busy Channel Lock-Out
Transmit Over Beeper
Dual Watch/Monitor
Receive Saver
Auto Keypad Lock
Voice Prompt
Power-on Display setting
Repeater Shift setting
Display Channel Name
2
3
3
5
5
6
7
7
8
9
10
10
12
12
14
16
19
20
20
20
20
20
21
21
22
25
30
30
31
31
32
32
32
33
33
33
33
34
34
34
35
35
35
35
36
36
37

CONTENTS
USING TIPS
UNPACKING AND CHECKING EQUIPMENT
Supplied Items
CHARGING BATTERY PACK
Charging Preparation
Charging Operation
INSTALLATION OF ACCESSORIES
Installation of Battery Pack
Antenna Installation
Installing Belt Clip
Installing External Micro/Speaker
Wrist Strap Installation
GETTING FAMILIAR
Radio Illustration
LCD Display
Keypad Functions
MODEL VERSION
WORKING MODE
Frequency Mode (VFO)
Frequency-Channel Mode (MR)
Channel Mode (CH)
FM Radio Mode
MENU Mode
Reset Mode
SET MENU MODE
SHORTCUT MENU OPERATION
DETAILED FUNCTION DESCRIPTION
Scan & Scan Mode setting
Priority Transmit
VOX Level & VOX Switch
TX Power setting
Squelch Adjustment
Dual Wait/Standby
LED Display Mode
Background Light Color
Keypad Beeper setting
Automatic Number Identity
Transmitter Time-Out Timer
Busy Channel Lock-Out
Transmit Over Beeper
Dual Watch/Monitor
Receive Saver
Auto Keypad Lock
Voice Prompt
Power-on Display setting
Repeater Shift setting
Display Channel Name
2
3
3
5
5
6
7
7
8
9
10
10
12
12
14
16
19
20
20
20
20
20
21
21
22
25
30
30
31
31
32
32
32
33
33
33
33
34
34
34
35
35
35
35
36
36
37

User's Manual
Tone coder & Tone Search Scanning & Tone calling
VFO Step setting
Wide/Narrow Band Selecting
Voice Mode and Scrambler
ADVANCED FUNCTIONS
PTT ID setting
Emergency Alert
Keypad Lock setting
Reverse Frequency
Tone Calling (1750Hz)
Channel Storage/Delete
FM Radio Function
Wire Clone
OPTIONAL SIGNALINGS
DTMF Part
MSK Part
2-Tone Part
5-Tone Part
REMOTE KILL, STUN, ACTIVATE AND REVIVE
TECHNICAL PARAMETERS
USING TIPS
UNPACKING AND CHECKING EQUIPMENT
37
40
41
41
42
42
43
43
43
44
44
46
47
50
51
52
54
56
59
64
www.maas-elektronik.com

User's Manual
Tone coder & Tone Search Scanning & Tone calling
VFO Step setting
Wide/Narrow Band Selecting
Voice Mode and Scrambler
ADVANCED FUNCTIONS
PTT ID setting
Emergency Alert
Keypad Lock setting
Reverse Frequency
Tone Calling (1750Hz)
Channel Storage/Delete
FM Radio Function
Wire Clone
OPTIONAL SIGNALINGS
DTMF Part
MSK Part
2-Tone Part
5-Tone Part
REMOTE KILL, STUN, ACTIVATE AND REVIVE
TECHNICAL PARAMETERS
USING TIPS
UNPACKING AND CHECKING EQUIPMENT
37
40
41
41
42
42
43
43
43
44
44
46
47
50
51
52
54
56
59
64
www.maas-elektronik.com

02 03
Obey the local government regulation before using this radio, improper use may violate
the law and be punished.
Turn off the radio before entering flammable or explosive areas.
Do not charge or change the battery in flammable or explosive areas.
Turn off the radio before getting close to the blasting zone or detonator areas.
Do not use radio whose antenna is damaged, touching of damaged antenna will cause
heat injury.
Do not attempt to open the radio; the maintenance work should be done by technical
expert only.
To avoid troubles caused by electromagnetic interference or electromagnetic
compatibility, please turn off the radio in places where have the banner "Do not use
wireless equipment", such as hospital and other healthcare places.
In the car with an airbag, do not put the radio within the scope of the airbag deployment.
Do not store the radio under the direct sunshine or in hot areas.
When you transmit with the radio, do keep away from its antenna for 5cm at least.
If the radio appears smelly or smoke, please shut off its power immediately and contact
with your local dealer.
Do not transmit too long, for the radio may heat and hurt the user.
Please read the following brief instructions, non-compliance with these rules may cause
danger or violate the law.
USING TIPS UNPACKING AND CHECKING EQUIPMENT
Transceiver (1)
Supplied Items:
to use AHT-28-V/AHT-78-U.

02 03
Obey the local government regulation before using this radio, improper use may violate
the law and be punished.
Turn off the radio before entering flammable or explosive areas.
Do not charge or change the battery in flammable or explosive areas.
Turn off the radio before getting close to the blasting zone or detonator areas.
Do not use radio whose antenna is damaged, touching of damaged antenna will cause
heat injury.
Do not attempt to open the radio; the maintenance work should be done by technical
expert only.
To avoid troubles caused by electromagnetic interference or electromagnetic
compatibility, please turn off the radio in places where have the banner "Do not use
wireless equipment", such as hospital and other healthcare places.
In the car with an airbag, do not put the radio within the scope of the airbag deployment.
Do not store the radio under the direct sunshine or in hot areas.
When you transmit with the radio, do keep away from its antenna for 5cm at least.
If the radio appears smelly or smoke, please shut off its power immediately and contact
with your local dealer.
Do not transmit too long, for the radio may heat and hurt the user.
Please read the following brief instructions, non-compliance with these rules may cause
danger or violate the law.
USING TIPS UNPACKING AND CHECKING EQUIPMENT
Transceiver (1)
Supplied Items:
to use AHT-28-V/AHT-78-U.

User's Manual
05
CHARGING BATTERY PACK
INSTALLATION OF ACCESSORIES
CHARGING BATTERY PACK
1600
7.4V
Charging Precaution
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User's Manual
05
CHARGING BATTERY PACK
INSTALLATION OF ACCESSORIES
CHARGING BATTERY PACK
1600
7.4V
Charging Precaution
www.maas-elektronik.com

06 07
INSTALLATION OF ACCESSORIES
Installation of Battery Pack
1)
2)
Fit the supplied battery pack into the batter pack trough, then slide it toward the head to
insert it completely---in direction of arrowhead (Picture 1).
Push the battery pack lock to release the battery pack and slide it toward the bottom to
remove it out---in direction of arrowhead (Picture 2).
Picture 1 Picture 2
Indicator Display Status
Red
Green
Charging Operation

06 07
INSTALLATION OF ACCESSORIES
Installation of Battery Pack
1)
2)
Fit the supplied battery pack into the batter pack trough, then slide it toward the head to
insert it completely---in direction of arrowhead (Picture 1).
Push the battery pack lock to release the battery pack and slide it toward the bottom to
remove it out---in direction of arrowhead (Picture 2).
Picture 1 Picture 2
Indicator Display Status
Red
Green
Charging Operation

08 09
Antenna Installation
F
PTT
CALL
MONI
A/B
SCAN
PRI
VOX
23
1
PWR
SQL
DW
56
4
LED
COLOR
BEEP
89
7
*
LOCK
ANI
0
#
T-R
FM RADIO
EXIT
F
PTT
CALL
MONI
A/B
SCAN
PRI
VOX
23
1
PWR
SQL
DW
56
4
LED
COLOR
BEEP
89
7
*
LOCK
ANI
0
#
T-R
FM RADIO
EXIT
Picture 3 Picture 4
Picture 3
Picture 4
Picture 5 Picture 6
SP
MIC
PUSH
SP
MIC
PUSH
Installing Belt Clip

08 09
Antenna Installation
F
PTT
CALL
MONI
A/B
SCAN
PRI
VOX
23
1
PWR
SQL
DW
56
4
LED
COLOR
BEEP
89
7
*
LOCK
ANI
0
#
T-R
FM RADIO
EXIT
F
PTT
CALL
MONI
A/B
SCAN
PRI
VOX
23
1
PWR
SQL
DW
56
4
LED
COLOR
BEEP
89
7
*
LOCK
ANI
0
#
T-R
FM RADIO
EXIT
Picture 3 Picture 4
Picture 3
Picture 4
Picture 5 Picture 6
SP
MIC
PUSH
SP
MIC
PUSH
Installing Belt Clip

User's Manual
Picture 7
F
A/B
123
SCAN
PRI VOX
456
PWR
SQL
DW
78
9
LED
COLOR
BEEP
FMRADIO
0
LOCK
ANI T-R
EXIT
Picture 8
SP
MIC
PUSH
GETTING FAMILIAR
10
Installing External Micro/Speaker
Wrist Strap Installation
www.maas-elektronik.com

User's Manual
Picture 7
F
A/B
123
SCAN
PRI VOX
456
PWR
SQL
DW
78
9
LED
COLOR
BEEP
FMRADIO
0
LOCK
ANI T-R
EXIT
Picture 8
SP
MIC
PUSH
GETTING FAMILIAR
10
Installing External Micro/Speaker
Wrist Strap Installation
www.maas-elektronik.com

MONI
PTT
CALL
12 13
RADIO ILLUSTRATION
BUSY/TX
The indicator turns green
during receive and turns
red during transmit/
emergency alarm.
MIC
The internal microphone
is located here.
POWER/VOLUME DIAL
This control toggle the
transceiver’s power on/off and
adjust the audio volume level.
SPEAKER
The internal speaker is
located here.
KEYBOARD
These 18 keys select the
operating features on the
transceiver. The function
of the keys are described
in details on pgs. 16&17.
ANTENNA
Connect the supplied
antenna here.
SP
MIC
CALL
Activates T-CALL (1750Hz) for
repeater access and transmit
DTMF and 2/5 tone signaling.
PTT
Press it to transmit and release
it to receive after your
transmission is completed.
MONI
Press this key disables the
noise squelching action,
allowing you to hear very weak
signals near the back-ground
noise level.
MIC/SP
The jack provides connection
points for microphone audio,
earphone audio, speaker and
program cable.

MONI
PTT
CALL
12 13
RADIO ILLUSTRATION
BUSY/TX
The indicator turns green
during receive and turns
red during transmit/
emergency alarm.
MIC
The internal microphone
is located here.
POWER/VOLUME DIAL
This control toggle the
transceiver’s power on/off and
adjust the audio volume level.
SPEAKER
The internal speaker is
located here.
KEYBOARD
These 18 keys select the
operating features on the
transceiver. The function
of the keys are described
in details on pgs. 16&17.
ANTENNA
Connect the supplied
antenna here.
SP
MIC
CALL
Activates T-CALL (1750Hz) for
repeater access and transmit
DTMF and 2/5 tone signaling.
PTT
Press it to transmit and release
it to receive after your
transmission is completed.
MONI
Press this key disables the
noise squelching action,
allowing you to hear very weak
signals near the back-ground
noise level.
MIC/SP
The jack provides connection
points for microphone audio,
earphone audio, speaker and
program cable.

14 15
LCD DISPLAY
You will see various icons shown on the screen when power on. The following table can
help you identify icons’ meaning which display on LCD.
Description of functions
Operating band signal & power meter
Low TX power active
Dual watch/standby active
RX power save active
VOX active
Repeater shift direction
Reverses the transmit and receive frequency active
Narrow band mode active
Keypad lock active
Icons
Description of functions
Squelch active
Beep tone active
Receive calling ID or MSG
Scrambler active
Battery power indicator
CTCSS decoder active
DCS decoder active
5 Tone signaling active
2 Tone signaling active
DTMF signaling active
Operating A band indicator
Operating B band indicator
Frequency mantissa indicator
Channel number/Menu items number indicator
Busy channel indicator
Channel scanned available under CH mode
Icons