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iSimple TranzItBlu ISFM21

Wired Bluetooth® adapter — connects an Android™ device to your factory radio

8 Reviews | 2 questions - 4 answers

Item # 541ISFM21

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Our take on the iSimple TranzItBlu ISFM21

So you don't want to have unsightly wires hanging all over your dash? iSimple has you covered. Using the Bluetooth audio streaming technology, the TranzItBlu Bluetooth adapter receives audio wirelessly from your Android phone, then sends it to your factory radio.

Get audio streaming with the factory radio

So you don't want to have unsightly wires hanging all over your dash? iSimple has you covered. Using the Bluetooth audio streaming technology, the TranzItBlu Bluetooth adapter receives audio wirelessly from your Android phone, then sends it to your factory radio.

Let's get connected

The TranzItBlu package includes an AM/FM antenna connection and a set of RCA outputs. You can connect the RCA outputs to your factory radio's auxiliary input for a direct audio connection, then hardwire the 12-volt power and ground connections for the iSimple TranzItBlu.

If your factory radio doesn't have an auxiliary input, you're still in good shape. You can use the TranzItBlu's FM antenna connection to link into the antenna connection on the back of your radio. That way, you're essentially "broadcasting" the audio signal to an unused FM frequency on your factory radio — you can choose from four selectable FM frequencies. If you live in a problem area, you can download a TranzItBlu app that lets you choose any frequency on the FM range, eliminating audio interference problems from other radio stations.

Important Note: If your factory radio does not have an aux input, please call an Advisor at 1-888-955-6000 to see if any antenna adapters or tools are needed to connect this Bluetooth module to your radio's antenna input.

Product Highlights:

  • provides Bluetooth audio streaming that works with an Android device and a factory radio
  • hideaway module that keeps the stock look
  • automatically reconnects with paired Android device
  • works with FM antenna connection or factory auxiliary input
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • iPod Bluetooth/FM transmitter interface module (w/ 41" power/ground leads and 24" Motorla antenna connections
  • On/Off switch (w/ attached 39" harness)
  • Instruction Booklet
  • TranzltBLU APP User Manual

iSimple TranzItBlu ISFM21 Reviews

Average Customer Review(s):

(8 Reviews)

tinny, hollow sounds

Cruz from New Jersey on 1/15/2015

Crutchfield Customer Review (What's this?)

Honestly for the price tag you may think you're getting a high quality product but it just isn't. To sum this up briefly; the sound cones through very tinny, very hollow. It sounds like you're listening to music in another room with a small aluminum tube in the wall. Just terrible. Switching to and from CDs and radio, the sound is amazing, but once this device is on, it all goes bad. Don't buy it, not for this price, you're gonna regret it!

Pros: If not for bad sound, Bluetooth is convenient. Connects quickly. Installation isn't so bad, very easy and straight forward.

Cons: Hollow, tinny sound. Very distant. Unknown reverb. Quality of sound is terrible.

Crutchfield response on 1/19/2015 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Isfm21 for android

FF coffin from Muskegon, MI on 1/5/2015

Crutchfield Customer Review (What's this?)

Works like it said it would

Pros: Quick install and easy to set yo

Cons: Lost over half of my radio stations by using the antenna set up

iSimple TranzItBlu ISFM21

Anonymous from Central, FL on 12/3/2014

Crutchfield Customer Review (What's this?)

The system was extremely easy to install the directions were spot on and the installation of the system was done in less than 20 minutes

Pros: The system worked flawlessly, once installed the music was streamed and sounded great. Ease of installation, simple easy to follow instructions and under one hour to have it all complete

Cons: The only con is it might take two tries to connect to your Bluetooth device, make sure to ask for the antenna cables otherwise you will be calling Crutchfield for them to be overnighted to you. They are not listed in the parts list as required parts

Crutchfield response on 12/9/2014 This adapter is a cool product that is proving to be quite popular. Sorry to hear that you ran into that antenna adapter problem - not all cars use the standard FM antenna connector. That's why we warn everyone up front on the product's webpage that if your stereo doesn't have an aux input, you might need an antenna adapter (last paragraph on the Overview tab). Glad to hear we were able to take care of you right away.


Android in SAAB from Upstate NY on 8/3/2014

Crutchfield Customer Review (What's this?)

Wanted to connect my phone to the factory radio which has no aux input or Bluetooth, this seems to be the best option. After some attempts this device did pair with my phone and sounds much better than the FM broadcast units that suffer from interference when travleing in areas with many stations. Although this model is described as working with Android my daughter's Apple 4S also paired with it. Initially I did not use then enclosed switch, but found the tranzltBLU did not turn off when unpairing the phone to use the radio. This prevented use of the radio, so I have added this switch now. I also think my FM radio signal may be reduced by placing this inline. FM stations that were always clear now have some occasional static.

Pros: Best option I have found to attach a smart phone to a factory radio

Cons: Small reduction in signal strength in normal operation.

iSimple TranzItBlu ISFM21

Jeff from Asheboro, NC on 7/3/2014

Crutchfield Customer Review (What's this?)

Great product from isimple.if your vehicle lacks bluetooth and you want to stream your music or movies from your phone this product works great.wish i had found out about this sooner.been shopping from Crutchfield sense 1995 and everything i have bought has been awesome!.hope this helps just make sure to install the included switch.

Pros: instantly streams bluetooth audio from device

Cons: none

iSimple TranzItBlu ISFM21

Opere0507 from Mt olive, NC on 4/8/2014

Crutchfield Customer Review (What's this?)

No too bad to install , but signal will drop.

Pros: Fairly easy to installation.

Cons: Will not stay connected.

great product

D C from San Diego, CA on 1/22/2014

Crutchfield Customer Review (What's this?)

I just had this product installed by a friend at audio shop. took him about 20 mins..if that. a couple of slices and bam. the product should crystallllll clear. really. I like it. there is one . awesome.

Pros: a lot.. I know have streaming music from android. music is soooo clear..great listening experience easy installation

Cons: delays in Pandora sometimes will kick you out and make sure you connect the power to a source that will cut the product off with the car. if you, you have to remember to flip the switch off

iSimple TranzItBlu ISFM21

octavio from Pembroke Pines, FL on 10/25/2013

Crutchfield Customer Review (What's this?)

It works great keep factory look

Pros: None

Cons: Bluetooth and aux cable


Hands-on research

Product Research


Overview: The iSimple TranzIt BLU (ISFM21) lets you listen to your Android smartphone or tablet through your vehicle's factory radio's FM tuner or Auxiliary input using Bluetooth technology. You'll be able to listen to stored music, music apps, audiobooks, podcasts, and more from your compatible Android device through your vehicle's factory stereo.

Compatibility: The iSimple TranzIt BLU (ISFM21) is compatible with Bluetooth-enabled Android smartphones and tablets. It can connect to almost any factory or aftermarket in-dash head unit which features an FM tuner or Aux input.

Installation Options: The iSimple TranzIt BLU features a wired FM transmitter with Motorola antenna input/output connections and is fitted with stereo RCA outputs, so it can connect to your factory radio via its FM radio or auxiliary input.

  • For a wired FM transmitter installation, you will need to unplug your factory antenna from your factory radio. The TranzIt BLU's male Motorola connector will plug into your factory radio's antenna port and your factory antenna will then plug into the TranzIt BLU's female Motorola jack.
  • Using the stereo RCA outputs, you can connect the TranzIt BLU to your factory radio's auxiliary input (if equipped). An RCA-to-minijack adapter (sold separately) may be needed.
Note: The TranzIt BLU also requires a hardwire power and ground connection.

Bluetooth Operation: The iSimple TranzIt BLU features built-in Bluetooth A2DP. Once connected to your factory radio, the iSimple TranzIt BLU wirelessly receives audio from your compatible Android device via Bluetooth, and then sends the audio to your factory head unit via FM radio or Aux input. Now, you can listen to stored music and music apps on your Android Bluetooth-enabled device through your factory stereo. You'll will continue to control your music and music apps from the Android smartphone or tablet.

Note: Your Android Bluetooth-enabled device will need to be paired with the iSimple TranzIt BLU. After being paired, the TranzIt BLU will automatically reconnect with your Android device when returning to the vehicle.

FM Frequency Selection: The factory-set operating frequency is 88.3 FM. If an alternate frequency (106.3 or 87.9) is desired, the frequency may be easily adjusted using the selector switch on the side of the module. For full frequency tuning control, download the TranzIt Blu app for your Android device. Make sure your factory radio is tuned to the same frequency.

Auto Interrupt + Toggle Switch: The TranzIt BLU automatically interrupts the incoming antenna signal when in use, to deliver audio from your Bluetooth-enabled Android device to your car stereo. To regain standard FM operation without interruption, simply pause the Android device, and approximately 8 seconds later the full FM band will be accessible again. If manual power on/off control is desired, you can connect the included toggle switch to the TranzIt BLU's power harness, so you can manually turn the TranzIt Blu on or off at any time.

Note: If you are using the TranzIt BLU's auxiliary output, simply select the Aux input on your in-dash receiver to hear audio from your Bluetooth-enabled Android device.

TranzIt BLU App: The free TranzIt BLU app from the Google Play App Store contains provides full control of the iSimple TranzIt BLU interface through your Android smartphone or tablet (requires Android 2.1+). The app allows for infinite channel selection, an auto power on/off, and manual on/off option. The TranzIt BLU app enhances control of the iSimple TranzIt BLU interface through your compatible Android device, but is not required for basic operation.

  • On/Off/Auto: On (turns FM radio interface on and keeps it on while App is running), Off (turns FM radio interface off), Auto (automatically turns FM radio interface on or off according to Bluetooth A2DP activity).
  • FM Broadcasting Frequency: Provides full-frequency tuning control to tune the best performing FM frequency.
  • FM Radio Region: Allows selection of FM radio region; North America, Japan, or Europe.
Note: Using AUTO mode and while listening to certain sources of music (such as Pandora) that have extended pauses between songs, it is possible that the radio interface of the TranzIt BLU will disengage. When this occurs, the FM radio will play through your car stereo again momentarily. Once the next song begins, the TranzIt BLU will reengage and your Android device will play through your car stereo again. The TranzIt BLU behaves this way due to the Bluetooth A2DP signaling. If this functionality is not desired, you can choose not to use the AUTO setting and instead select ON in the TranzIt BLU App. This will provide a less disruptive listening experience.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

2 questions already asked

You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this will integrate. If it does not, then they will also be able to discuss other options with you. [ Krissy  Feb 09, 2014 ]  Staff
Nope! [ KENTON E  Jan 14, 2014 ]
Hi aBilly M: No unfortunately you can't. I put this in my daughters' 99 grand am and she has an android phone. When she gets a call the unit turns off so she can take the call. If you had a stereo capable of doing hands free, then you probably wouldn't need this device. I think crutchfield does have some radios that would give you that capability, but maybe that's more than you had in mind. Other than that the unit was very easy to install and works great at letting her listen to her tunes on her phone through the cars stereo. Hope that is some help to you. have a good day,Si [ Siebert  Jan 13, 2014 ]
No. It doesn't have any phone controls or a microphone input that you would need to make hands free calls. Basically its just a one way device that streams music only. [ Jeff  Jan 13, 2014 ]