REI ST-4050 User manual

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Radio Engineering Industries, Inc.
www.radioeng.com
Rev A.0 Date: 4-10-19
Heavy Duty Digital Media Receiver with Short Chassis Design, AM/FM
Stereo Weather Band Radio, USB iPod® Control and Charging,
Front/Rear Auxiliary Inputs and built in PA
Installation/ Operation Manual
50W x 4 ST-4050

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Thank you for purchasing ST-4050 AM/FM/CD Receiver from REI. This product is
designed and tested to with stand temperature and vibration extremes. Please read the
owner’s manual carefully before attempting to install this unit.
If you have an installation question or need installation assistance, please call the:
SERVICE HOT LINE
1-877-726-4617 Toll Free USA & CANADA
FEATURES:
Heavy Duty construction for Tough Environments
Compact Chassis Design, less than 3” mounting depth
Non-volatile memory back-up stores user settings when battery is disconnected
Clock Memory with EEPROM stored Presets
Output Power 50W x 4
7 channel NOAA® Weather Band Tuner
Electronic AM/FM Stereo Tuner w/RBDS
Preset Up to 30 Radio Stations (18 FM, 12 AM)
EURO and USA frequency bands
White LED backlighting
MP3/WMA playback w/ ID3 Tag Support
2 Aux Inputs (Front 3.5mm Stereo Jack/Rear RCA)
iPod® /iPhone® Charging and Playback Control via USB
Rear Channel RCA Line outputs
Built in Selectable PA input (Microphones & Adapter Sold Separately)
ISO Connector for vehicles manufactured with the ISO connect harness
IF ADDITIONAL INSTALLATION COMPONENTS ARE NECESSARY, CONTACT YOUR
REI SALES REP FOR:
** OEM /FACTORY WIRING HARNESS ADAPTERS
** ANTENNAS & ANTENNA ADAPTERS
** SPEAKERS & GRILLS
Radio Engineering Industries, Inc.
6534 “L” Street
Omaha, Nebraska 68117
[phone]
www.radioeng.com
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NOTES:

18 3
CONTROLS AND INDICATORS
1. Power/Mute Button
2. Volume/Select Knob
3. Scan /Search Button
4. Band Button
5. Tune /Seek/Track Down Button
6. Tune /Seek/Track Up Button
7. Preset Memory/Recall, Media Control Buttons
8. Front USB Input
9. Back Button
10. Display Button
11. Source Select Button
12. Reset switch
13. Front AUX1 Input Jack
14. LCD Display

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OPERATION
1) POWER/MUTE Button
Press the Power Button to turn the unit ON or hold to turn the unit OFF. The button
will illuminate RED when OFF and BLUE when ON. When ON, press to MUTE the
audio on/off. Note: Radio can also be powered on by pressing any front button.
2) VOLUME/SELECT Knob
Rotate the knob left or right to change the volume level.
Press the knob to select one of the following functions:
VOL---BASS---TREB---BAL--FAD
Upon choosing the function, rotate the knob to adjust the desired setting.
PLEASE NOTE: If the Volume/Select Knob has not been adjusted for 3 seconds it
will automatically revert back to the previous informational display.
Press and hold this button to access the radio SETUP MENU.
3) SCAN/SEARCH Button
Press and hold this button for 2 seconds to auto program available stations into the
preset memory buttons. This function will erase previous memorized stations and
store the newly searched stations. Once completed, the radio will scan for 5 seconds
through each of the preset stations of either the AM or FM band and stop.
4) BAND Button
Press this button to change radio bands as follows:
FM1—FM2—FM3—AM1—AM2—WB
5) TUNE/SEEK DOWN Button
Under Radio mode, press this button momentarily to manually tune downward. Press
and hold a button and the radio will automatically seek to the previous radio station.
When playing digital media, use this button to track backwards to the previous track.
This button also functions as Weather Band Channel access. Under Weather Band
mode, press this button to select Weather Band channels 1-7.
6) TUNE/SEEK UP Button
Under Radio mode, press this button momentarily to manually tune upward. Press
and hold a button and the radio will automatically seek to the next radio station.
When playing digital media, use this button to track forwards to the next track.
This button also functions as Weather Band Channel access. Under Weather Band
mode, press this button to select Weather Band channels 1-7.
7) Preset Memory/Recall Buttons 1-6
Press these buttons momentarily to select the preset stations.
Press and holding a button will set the current station to the button being pressed.
**Preset buttons are pre-assigned frequencies in Weather Band Mode.
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SPECIFICATIONS
AUDIO SECTION
Power supply voltage (negative ground) ……………….……….12V DC (10V-18V)
Standby Current…...……………………..…………..……………….……..…<5mA
Max Current Consumption……….……………………….……….….……….....10A
Speaker impedance …………………….……………….….…4-8 Ohms per channel
Maximum Pre-output Voltage……….…........................................2.0Vrms/10k ohms
POWER OUTPUT
Continuous Output into 4Ω, @1KHz at 10 % THD …………..…...……4 x 25Watts
Maximum Power Output (Volume control Maximum)……….…...50W×4 (at 1kHz)
FM TUNER
Range ………………………………………….…(USA 200 kHz) 87.5 – 107.9 MHz
(EUR 50 kHz) 87.50 – 108.00 MHz
Usable Sensitivity (S/N = 30dB)…………………………...7.34dBf.(0.6uV/75ohms)
Signal to noise ratio ………………………………….………………...58dB (Mono)
Stereo separation (@ 1K Hz) ………………………….……..……………..…42 dB
AM TUNER
Range ………………………………………………..(USA 10 kHz)530 – 1,710 kHz
(EUR 9kHz) 522 – 1,620 kHz
Usable Sensitivity (S/N = 20dB)………………………..………....23dBuV (14.4uV)
Signal to noise ratio (LEVEL60dbuV)…….………………...………………... 60 dB
WEATHER BAND TUNER
Range …………………………………………………..…….162.400 –162.550MHz
Usable Sensitivity (S/N = 20dB)……………………..………………0.7uV(-9dBuV)
Signal to noise ratio (LEVEL40dbuV)…….…………………...……………….42dB
USB INTERFACE
USB Standard……………………………………………….USB1.1/2.0 (Full Speed)
Maximum Supply ……….…………………………………………………...5V/1.5A
File System…………………………………………………………………..Fat16/32
AUXILIARY INPUT SPECIFICATIONS
Input Voltage Maximum Voltages..……………………………………………...1.2V
Frequency Response (+/- 1dB)……………………………...…………20 – 20,000Hz
Input impedance………………………………………………………………..10KΩ
DIMENSIONS
Chassis (W x H x D) ………...……………….1882m (7”) x 54mm (2”) x 75mm(3”)
Nosepiece (W x H x D) ……….….188mm (7-3/8”) x 58mm (2-1/4”) x 18mm (5/8”)
Weight ……………………………………………….…………………………1.2Ibs
*Due to continuous product improvement, specifications and design are subject to
change without notice.
5
8) USB Input
Insert a USB drive and the radio will automatically switch to USB input and begin
playback.
9) BACK Button
Press this button to navigate Backwards when in Apple playback modes:
10) DISP Button
Press to change the display information
To set the Time:
With the radio’s BLUE power light ON, press and hold this button until the hour
display begins to flash. Rotate Volume/Select Knob to adjust the hour. Press the DISP
button again, and the minute display will flash. Rotate VOL/SEL Knob to adjust the
minute. Press either the DISP or VOL/SEL button to save the time on the LCD.
11) SRC Button
Press this button to navigate between source modes:
TUNER—USB(when connected)—AUX1—AUX2.
12) Reset Switch
In the unlikely event that the radio is not operating correctly, press the RESET button
to restart the operating system of the radio.
13) Front AUX 1 Input Jack
The unit is equipped with a front panel 3.5mm auxiliary input (AUX 1) so you can
connect your external portable audio player or portable satellite radio receiver. A
second REAR (AUX 2) RCA jack is also included on the rear of the radio.
14) LCD Display
Display shows the radios operational information.

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WEATHER BAND MODE
NOAA National Weather Radio Broadcasts from over 380 Locations throughout
the U.S. on seven VHF/FM frequencies. Tune to receive continuous weather
information 24 hours a day on one of the following frequencies.
For local station listing see: http://www.nws.noaa.gov/nwr/nwrbro.htm
Press preset 1 to select weather band channel 1 - 162.400MHZ
Press preset 2 to select weather band channel 2 - 162.425MHZ
Press preset 3 to select weather band channel 3 - 162.450MHZ
Press preset 4 to select weather band channel 4 - 162.475MHZ
Press preset 5 to select weather band channel 5 - 162.500MHZ
Press preset 6 to select weather band channel 6 - 162.525MHZ
**Press SEEK UP/DOWN to select weather band channel 7 - 162.550 MHz
SETUP MENU
With the unit ON, press and hold the VOL/SEL button for 2 seconds. LCD will
display MENU. Rotate the VOL/SEL knob to choose the option, then press to make
a selection:
 SCROLL ON/OFF
Choose how iPod/iPhone®, and ID3 tag information is displayed on the LCD. With
the scroll set to ON, information is repeated continuously on the front display. When
set to OFF, information is not displayed unless the user presses the DISPLAY button.
 LOUD ON/OFF
Choose to turn LOUNDNESS ON or OFF.
 RDS ON/OFF
Choose to turn the RDS (Radio Broadcast Data System) Scrolling display ON or OFF.
 MIC CARBON/DYNAMIC
The first option is to select a correct PA input based on the microphone type you are
using. Rotate VOL/SEL button to choose type:
DYNAMIC
Microphone does NOT have on on-board volume control. PA volume
control is built into the radio. Key the microphone to make adjustments.
CARBON
Microphone has on on-board volume control. Radio will not control the
volume.
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TROUBLE SHOOTING
Problem Cause Solution
Radio will not power up No power to BATTERY wire or blown 10A
main fuse.
Check for both ACC & BATTERY voltage
with Multi-meter, check all fuses.
No sound Speakers not connected; speakers connected
with bad splices; Speakers shorted to ground;
speaker load is not within 4-8 Ω.
Connect speakers to harness; check all
spliced wires; verify speakers not shorted to
chassis; verify total speaker impedance.
Check volume level.
Public Address can NOT be audible over
speakers
PA setting in MENU is wrong; microphone is
pinned wrong; wrong microphone type is used.
Microphone is defective.
Turn the volume up on the microphone or
radio when the LCD display’s MIC; Check
that the correct microphone type is
connected. Check the PA setting’s in the
radio’s menu.
LCD Display says MIC and front controls
are locked
PA system is triggered Remove microphone connection and verify
correct pinning and or type, replace
microphone. Reset the unit.
Cannot tune radio stations The antenna cable is not connected. The signal
is too weak. The radio is in the wrong
frequency steps.
Connect the antenna cable. Check the
frequency spacing in the radio’s SERVICE
menu.
USB media not playing, or says loading. Media is the wrong file type. Convert files to a usable format, see file
requirements section of the manual.
Audio is distorted or low. Source audio level is too weak or overdriven.
Bitrate of audio file is too large.
Adjust the volume level of the auxiliary
source. Change the sample frequency or
Bitrate of the file.
iPod® screen displays “loading” for a long
period of time.
Device is not a supported device. The radio
supports a majority of iPod® models, but not all
are guaranteed.
Wait for iPod® to load or reconnect 30-pin
plug. If still loading, then device is not
supported, or has low battery. Use the
AUX input or a Bluetooth® connection
instead.
The Radio does NOT respond to the front
buttons
An error in operation has occurred Reset the unit from the front panel.
The Radio does not charge my device The device requires additional current via the
USB to charge the device
Unplug and try again. The USB cannot
support more than 5V/1.5A.

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3. If additional support is needed, bend the included support bracket, and secure it
to the vehicle using a screw. Secure the opposite end to the radio’s rear stud using the
nut and washer provided.
4. To remove the radio, insert the two release keys into the holes on the front face of
the radio. The tools must be inserted with the notched side facing the radio. Slide the
keys foreword until you hear a click. Then pull the radio out, releasing it from the
DIN collar.
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 VER XXXX
This is the firmware version present on the radio. Not all features described
in this manual may be available on the radio at this time.
To save and exit MENU mode, press and hold the VOL/SEL button.
Note: Menu will exit automatically after 5 continuous seconds without saving any
selections.
RADIO OPERATION
1. Preset Number
Displays the Preset Channel of the frequency.
2. AM/FM/WB Band Preset Mode
Press the BAND button to switch from FM1, FM2, FM3, AM1, AM2, or WB
display on the left
3. Frequency Display
Displays the Frequency of the current tuned station on the right side when not in
RDS mode
4. Stereo Indicator
Displays when the FM frequency is tuned in Stereo.
Radio Broadcast Data System
This unit is equipped to display RBDS (Radio Broadcast Data Service)
information if broadcast by the current radio station.
NOTE: Radio stations broadcasting RBDS may not be available in your listening
area.
1. RDS Display Indication
When RDS is set to ON in the MENU, FM station’s receiving RDS text will
display in this indicator.
2. FM Frequency Display
This area scrolls RDS text when RDS is set to ON.

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USB OPERATION
Connect a USB storage device to the unit. The radio will automatically switch
MODE’S and begin playback after the media is successfully loaded. Use the
SEEK UP/DOWN buttons to change tracks. use the FOLDER UP/DOWN
buttons to select the desired folder for playback.
Press this button to REPEAT ONE, DIR, ALL, or NONE
Press this button to turn RANDOM ON/OFF
Press this button to PAUSE/PLAY the media
1. USB Detect
Display when a USB device is connected to the unit. Provides 1.5A charge current
when connected to compatible devices.
2. Shows the Track, Folder and ID3 tag information file
Press the DISPLAY button cycle from Title, Artist, Album or track information.
3. Playback Mode of Operation
Displays when RANDOM Mode is active.
4. Playback Mode of Operation
Displays when REPEAT Mode is active.
SUPPORTED AUDIO FILES (MP3/WMA using ISO9660 formatting FLAC/AAC/M4A/WAV)
Format Bit rate Samplin
g
Fre
q
uenc
y
Bit count
AAC-LC (.m4a) MPEG2/4 AAC LC
HE-AAC(V1,V2)
8 – 320kbps, VBR 16 – 48 kHz 16 bit
MP3 (.mp3) MPEG 1/2 Audio Layer 3 8 – 320kbps, VBR 16 – 48 kHz 16 bit
WMA (.wma) Windows Media Audio
Standard L3 profile
(Version 7,8,9)
8 – 320kbps 16 – 48 kHz 16 bit
Linear PCM (.wav) RIFF waveform Audio
Format
16 – 192 kHz 16 bit/24 bit
FLAC (.flac) flac 16 – 192 kHz 16 bit/24 bit
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INSTALLING THE RADIO
1. Place the DIN collar into the dash opening. Bend the tabs outward as shown on
the drawing below to lock into place.
2. Pass the harness and antenna cable through the DIN collar, and connect to the
back of the radio. Verify clearance; then gently insert the radio into the DIN Collar
until both spring clips are locked into place.

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ELECTRICAL CONNECTIONS
Follow this easy wiring diagram when installing Radio and Speakers.
Warning:
*This radio is designed for 12V DC Negative Ground Systems Only.
**Shorting or grounding any of the speaker wires can damage the radio and is not
covered by warranty.
**NOTE: BOTH THE RADIO’S BATTERY +12V & ACC +12V POWER
WIRES MUST BE CONNECTED FOR OPERATION.
REQUIRED RADIO DIMENSIONS
Verify the radio will fit by following the suggested dimensions below. Carefully cut or
file as necessary until the sleeve easily slides into the opening.
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iPod®/iPhone® OPERATION
To listen to audio through your apple device, verify that a Certified USB extension
is connected to the USB pigtail on the rear of the radio. Next, connect the USB
cable to the Apple device. Once connected, the radio will automatically switch
the source to iPod/iPhone® and begin charging the device. If the device has
enough battery power, it will begin playback.
When connected, the user can playback specific files or folders. First press the
SEARCH button.
The user can then rotate the VOL/SEL knob to select one of the following search
options:
 Playlists
 Podcasts
 Audiobooks
 Songs
 Albums
 Artists
Press the VOL/SEL knob to choose. To return to a previous menu, press
the RETURN button and choose again using the VOL/SEL knob.
Use the radio’s SEEK up/down buttons to change tracks, and the
button to PAUSE or PLAY the track. To return to the iPod/iPhone® source from
any other source menu, touch SRC on the front panel until the iPod/iPhone® icon
is shown on the front display.
AUX OPERATION
Press the SRC button on the front panel until the display shows either AUX 1 or
AUX2. AUX 1 uses the front 3.5mm audio input while AUX 2 uses the rear
RCA L/R audio inputs. It may be necessary to adjust the VOLUME level of the
AUXILARLY input device if too little or too much signal is present.

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PA OPERATION (microphone sold separately)
Connect a PA microphone into the 4-pin connector. Microphone has priority over
all other audio modes and mute’s the source audio being played when keyed.
When the PA is triggered, the front display will show MIC, until the trigger is
un-keyed. Any digital media being played at that time will be sent a PAUSE
command. Once released, it will return to the previous source mode at the
previous volume level. Any digital media will be given a PLAY command.
The PA operates regardless of radio status, as long as both ACC and Battery
power is applied to the radio.
When set to CARBON mode, the volume of the PA is only adjustable on the
microphone itself. When set to DYNAMIC mode, the volume level is adjustable
only when keyed from the front using the VOL/SEL button.
A rear view of the radio’s PA pin connection option is shown below:
Carbon PA Dynamic PA
iPod® and iPhone® are trademarks of Apple Inc., registered in the U.S. and
other countries. Functionality may vary by model number, operation is not
guaranteed.
The Bluetooth® word mark and logos are registered trademarks owned by
Bluetooth SIG, Inc. and any use of such marks by REI under license.
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6
1
2
5
3
4
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OPTIONAL REMOTE CONTROL
*Requires using an external IR extension cable sold separately.
(1) Power Button
(2) Language Button (N/A)
(3) Menu Button (N/A)
(4) Volume Up/Down Buttons
(5) Enter Button (N/A)
(6) Scroll Buttons
(7) Setup Button
(8) Mode Button
(9) Playback Buttons