
Portable card FM transmitter
Dear customer :
Thanks for ordering our portable plug in card type FM transmitter model HRD-831. This product build up with
High quality import electronic components , with super long power up to 20 hours , one button for mono / stereo audio
exchange , 16 sound level can be adjusted , with separate AUX audio input port , MIC microphone input port and key lock
function . Adjustable frequency 88.1-107.9 MHz ( can also set to fixed frequency )
good anti interference power for better security , suitable for tourist guide , training course , traveling , study activities .
Please read the manual in detail before use and keep the manual for later inquiry .
1) Product function diagram :
① LCD display
② TF card port ( support MP3 format )
③ Mic port
④ 3.5 mm AUX port
⑤ Power on / off button
⑥ PREV - frequency , volume increase switch , long press for mono / stereo interchange
⑦ NEXT - frequency , volume decrease switch , long press for frequency lock
⑧ MENU - interchange button for MIC / AUX / FM
⑨ ▷‖Play / pause
⑩ Lock switch
⑪ battery cover
⑫、Waistband

一、:Operation :
1. Push open battery cover , insert BL-5C Li battery , close battery cover
2. Long press power button ⑥ to power on,
(2.1) Internal MP3 playing : In condition no audio input in AUX port ⑤, insert TF card to enter MP3 playing mode ,
transmitter with automatically read card and play music , short press PREV⑦,NEXT⑧ for previous / next song , short
press ▷‖⑩ for play / pause
(2.2) Play external audio : connect AUX⑤port using audio cable to PC / TV / mobile to play external audio , unplug
audio cable in AUX playing mode will automatically change to TF card playing mode in 3 seconds.
(2.3) insert microphone to MIC port for chatting
3. Function interchange :
Short press MENU button , MIC / AUX / FM flashing in sequence。
When “MIC” flashing , short press PREV⑦,NEXT⑧ to adjust Mic volume
When “AUX” flashing , short press short press PREV⑦,NEXT⑧ to adjust AUX volume
When “FM” flashing , short press PREV⑦,NEXT⑧ to adjust frequency
( if transmitter locked frequency 88.1MHz , long press NEXT button for frequency exchange )
4. Lock / unlock method :
(1)In normal condition , long press LOCK button , icon appear in display , function locked.
(2) In locked condition , long press LOCK button to release locking function , icon disappear.
5. Charging
(1) Connect transmitter to DC5V charging adapter by USB charging cable , icon flashing to indicate charging in
process .
(2) Icon stop flashing upon fully charged , charging time around 5 hours
6. Long press PREV button for 2 seconds to interchange mono / stereo mode , STEREO appear on display is stereo mode .
二、Notice for operate the product :
1. Maintenance should be done by professional technician
2. Please do not use it in easy explosive circumstance ( such as gas station , steam room )
3. Please don’t place transmitter in high dusty , high temperature & high humidity condition.
4. Please follow the rules set by Administration of radio
5. Please don’t use the device in stormy weather.
三、Product feature :
1. This product using professional IC , high quality audio can be separate handled to obtain lossless audio
2. Professional level of noise wave / harmonic wave , ≤60dB , get rid of surrounding interference
3. Mono / stereo easily interchange , easy operate
4. Suitable applicant / organization
Driving college / school / stage director / public speech / tourist / vehicle mounted chatting , MP3 audio forward / in
house wireless audio system / wireless meeting system / simultaneous interpretation / outdoor traveling

Note :
88.1-107.9MHz(step value:0.2MHz)
8 hrs / 6 hrs / 5hrs / 3hrs level 1 to 4
noise wave / harmonic wave
radiation
Stereo , 1.2 M
with shielding
A、 Please recharge device when icon indicate empty .
B、 No charging indication when charging in power off status.
C、 Please release battery while long period not in use.
5. Main specification data :
6. Package :
7. After sell service :

Warranty card
Name: Tel:
Address:
Purchase date:
Product occur non human damage during normal use in 12 months warranty period can be served with free of
charge maintenance service ( not on-site repair ) , customer will be charged for reasonable repair cost in below
situation :
1、 Damage by self dis-assembly
2、 Operate device not following user manual
3、 Damage by human , broken , destroy , watering not relate to product quality
4、 Device damaged by thunder strike or irresistible issue
5、 Exist warranty period or can prove manufacturing date
6、 Product case , Lithium battery , microphone , charging adapter , audio cable & USB charging cable did not provide
free of charge maintenance
8. Disclaimer :
Please follow the rule set by Administration of radio we are not response for any claim related to this issue
FCC Compliance Statement:
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1)This device may not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
Important: Any Changes or modifications not expressly approved by the party responsible for compliance could void the user's
authority to operate the equipment.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the
FCC Rules.
These limits are designed to provide reasonable protection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions,
may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a
particular installation.
If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
-Reorient or relocate the receiving antenna.
-Increase the separation between the equipment and receiver.
-Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
-Consult the dealer or an experienced radio/TV technician for help.