Dock Connector Audio I/O


Several options exist for getting audio signal into and out of iPhone OS devices via the dock connector. However, not all accessories are compatible with all iPhone OS devices. So, we put together this compatibility chart, based on our own tests with SignalScope/Pro and SignalSuite.

Dock Audio Accessory Compatibility

These devices were chosen for their ability to accept stereo audio input from external sources. Some dock connector devices simply feature built-in microphones, which are of limited use for test and measurement applications. It’s also important to remember that the iPhone OS automatically selects the current route for input audio signals (built-in mic, headset, dock connector, etc).

iPhone iPhone 3G iPod touch iPod touch 2G
Alesis ProTrack In/Out(1,2) In/Out(2) Out(3) In/Out(2)
Belkin TuneTalk Stereo In(1) In In(3,4) In
Griffin iTalk Pro (5) In(5) In(5) In(3,4,5) In(5)
MacAlly iVoice Pro In/Out In/Out In/Out In/Out
Tunewear Stereo Sound Recorder In(1) In In(3,4) In
  1. Even when using the dock connector for input, if the receiver or built-in speaker is the current output device on the original iPhone, the sample rate will be limited to 8 kHz (for input and output). Connecting headphones, or an adapter cable, like a stereo mini-plug to RCA adapter, will cause the headphone output to be selected and push the sample rate back up to 48 kHz.
  2. In SignalScope Pro (or SignalScope) the Alesis ProTrack appears as an input only device, so output signals are not routed to the ProTrack’s headphone out connector. The ProTrack’s headphone output does work with SignalSuite.
  3. Using a dock connector input with the original (1st generation) iPod touch appears to require that something be plugged into the headphone jack, unless the dock connector device also supports audio output (like the Macally iVoice Pro, which, ironically, is one of the few devices that is narrow enough to allow you to simultaneously plug your headphones into the bottom of the iPod).
  4. When using the original iPod touch with standard dock connector input devices, like the TuneTalk or the Tunewear device, a dock extender, like the SendStation device, will be required in order to also plug in headphones. You need to be sure your dock extender supports audio (some do not).
  5. The Griffin iTalk Pro that we tested did not work consistently–sometimes it wouldn’t be selected for input by the device. For now, the iTalk Pro is not recommended.

Frequency response measurements of these devices can be found here.


  • Jan Sundström

    Ben, thanks a LOT for your research!
    This is invaluable information.

    Will you be able to test Blue Mikey and Logitec LIC-iREC03P for iPhone too in the future?!

    Thanks again,


  • Chapito

    +1 on the Mikey and Logitec 03P

    PS love your site- info top notch!!

  • Darren

    Did you verify individual channels on the MacAlly iVoice Pro with an iPhone 3G running 3.0.1? I bought one and while it’s internal microphone is fine, nothing comes in the right channel. I tried a pair of lavaliere mics and two different Y adapters with the switch set to mic. Regardless of which mic was hooked to which channel, only the left came through. I also tried the line in setting with input from a mixer. Left only again through a third Y adapter cable. Tried again in airplane mode with the same results. Either this one is defective or it’s stuck in mono mode somehow.

    • ben


      Both input channels work fine for me (on iPod touch, iPhone 3G, and iPhone 3GS). I tested it with iPhone OS 3.0.1 on the iPhone 3GS, but I don’t think it would be any different on the iPhone 3G.


  • Mark


    Just so I’m clear, does the Belkin TuneTalk Stereo take a stereo signal into iPhone 3GS running 3.0.1 ?


  • maxpy

    How to let iphone use dock connector pin 5 and 6 to recording the audio?

  • Tom Andersen

    Most of these devices have things that ‘line in people’ don’t need, like speakers, microphones, etc. It seems that a device could be made that has just one stereo line in plug on it.

    Ok so that does not exist. Which one appears the most sturdily built, and is easily ‘buyable’ today? I need to test them and also tell customers which one to buy. The iVoiceIII from macally looks smaller than the pro tested here. Does it work with a iPhone? I think I am buying an iVoiceIII – will report back.

  • Tom Andersen

    Ok – I bought a TuneTalk – it seems to be generally available. It works well on an iPhone 3G and 3GS, but there is a warning dialog about how this device is not built for the phone. It offers to turn airplane mode on, which is a good thing as interference is cut down.

  • Jason Smith

    The send station is pretty sweet if you just need a dock line out/in connector.

  • gregn

    Back on August 25, 2009, it was confirmed that the Belkin TuneTalk Stereo worked on an iPhone 3GS running OS 3.0.1. Does it still work under OS 3.1.2?

    I initially had success using a MacAlly iVoice III on an iPhone 2G running 3.0.1, but once I upgraded to 3.1.2, I got a message after about 10 seconds stating that “the accessory is not made to work with iPhone”. Once this happened, audio was no longer sampled by the device. The same thing happens on the 3GS.

    I just want to make sure the TuneTalk doesn’t behave the same way before I buy one.

    • ben

      Back on August 25, 2009, it was confirmed that the Belkin TuneTalk Stereo worked on an iPhone 3GS running OS 3.0.1. Does it still work under OS 3.1.2?


      I initially had success using a MacAlly iVoice III on an iPhone 2G running 3.0.1, but once I upgraded to 3.1.2, I got a message after about 10 seconds stating that “the accessory is not made to work with iPhone”. Once this happened, audio was no longer sampled by the device. The same thing happens on the 3GS.

      I haven’t tested the iVoice III, but the iVoice Pro works fine.

  • Kevin

    Do any of these devices provide simultaneous line level input and output? It seems like the iVoicePro might, but it is not clear if the audio input is mic level, or line level.

    • ben

      I’m not aware of any iPod/iPhone dock accessory that provides simultaneous line-in and line-out.


      • Kevin

        I think the iAudioInterface might be the first for simultaneous line-in and line-out. It is suppose to release soon.

  • Marc Urselli

    would love to read about the Blue Mikey and Logitec LIC-iREC03P…
    thanks for the handy comparison!
    Marc Urselli

  • Jonathan Richard

    Ben, I’ve looked on the Alesis website at the Protrack, but I don’t see anything to indicate that it can work with an iPhone. I don’t have an iPod touch, I have an iPhone 3GS — are the touch and the iPhone the same size and therefore interchangeable with the Protrack?

    Thanks for your help.


    • ben


      The iPhone 3GS works fine with the ProTrack. The problem is that you need to find your own method of securing it to the ProTrack. This is even true of the iPod touch, since, even though they show a picture of it, the clear plastic ProTrack sleds for iPod touch aren’t available, yet.

  • gc

    I’m confused. I looked at your site and concluded that the Belkin interface would work with our 2g, 3G or 3gs iphone. I then check other more recent sites and they say no! So, are they wrong or is your website evaluation due for an update. I really like your apps on the mac and was hoping to implement them on the iphone.

    • ben


      We have successfully tested the Belkin TuneTalk on all iPod touch and iPhone models (it’s a little tricky on the 1st gen iPod touch, but that’s already discussed in the notes above). Also, we have had success with it on iPhone OS 2.x and 3.x.


  • Tom

    from what I’ve read here I’ve understood that Ivoice Pro works with Iphone 3G FW 3.1.2 Is it right?

    And Ben, Can you do me a small favour? If I give you an app to try can you tell me if it works with Ivoice Pro?


  • Dan

    Hi. I have been reading all the above and would like to know in a sentence what can I connect to an iphone 3g with stereo line level input and what app records stereo line input. NO MICS needed

    • ben


      It’s not clear what you’re asking. All of the devices listed above can be used with an iPhone 3G. They all have mics, but I am not aware of any line input accessories that do not. If you just want to record stereo signals, then I recommend that you check out the various recording apps available for iPhone. If you want to analyze the input signals, SignalScope and SignalScope Pro are both capable of working with 2 input channels (stereo line input).

  • Greg

    I think he is refering to something that can plug into a 3g and provide line (5v) level inputs as apposed to mic level (1v)

  • Allen

    Ben how did you go about initialising the line-in functionality as i am trying to simply just adapt aurio touch to accept line in.

    • ben


      The iPhone OS automatically selects the audio input source, depending on what you connect to the device.


  • David

    Ben, thanks for interesting information.

    I need to master a couple of tracks, so that they sound good
    on an iPhone 3G speaker.
    So, I don’t really need to record audio, but need to pass line level signal into iPhone and hear it on internal speaker.
    Would it it possible to do it, with any of the above devices?
    Of course, the recording software must be able to monitor the signal.

    thanks, David

  • Odemar Costa

    Good Morning.

    Searching for Alesis Pro Track I found many posts about this device.
    But the majority of these posts are refered only with using on Ipod.
    I´d like to know if Alesis works OK on Iphone 3Gs?
    Thanks for this technical information. Odemar Costa.

    • ben

      The Alesis ProTrack works with the iPhone 3GS. However, the iPhone’s headphone jack will be covered by the ProTrack shield (which you have to purchase separately).

  • Alex

    this is the most interesting page I’ve found in the net about iPhone/iPod Touch dock pinouts for line input. However I still haven’t found a solution to my problem.
    I’m using an iPod Touch 2G with OS 3.1.2 (Jailbroken).
    I modded a dock cable in order to use the audio input pins (5 and 6) but it seems they are disabled.
    I also connected pin 11 to pin 15/16 (I didn’t try the modded cable without this last connection).
    I tried with and without the connection between pin 15/16 and 21 with a 68KOhm resistor (but there was no difference). In both cases the integrated volume control was disabled and the audio output was working ok (at a rather high volume).
    Maybe I have to choose a different resistor to indicate the kind of device I’m using? I wanted to register to the Made for iPod program, but I’m not a company, nor I have an app (yet).
    Anyone could help me to make stereo input work?
    Thank you in advance for your help,


    • ben

      I would still encourage you to apply to the Made for iPod program for access to iOS device specifications.

  • Alex

    Thank you for your anwser Ben, but I’ve already tried to apply. I just can’t proceed as I don’t have any “business license/certificate, tax license, commercial registration, or equivalent”.
    Anyway, my email is always valid…

    • ben

      This is not as difficult to do as you might think. A local business license might cost you $20 or $30 to set up as an individual (sole proprietor). The MFI program offers an adjunct licensee option that gives you access to the docs without any of the reporting requirements of full membership. If you contact Apple, they may allow you to get signed on as an adjunct licensee for the purpose of allowing you to get the necessary information to evaluate the potential business opportunity for iPhone accessory development.

      • Alex

        I may try to contact Apple… However it’s ridiculous that I have to pass through all this to get a simple information. All I (and many other people) want is to get audio input working.

  • Dan

    I am trying to convert analog audio from my tape player using iPhone 4. I need stereo line-level input into the iPhone 4. please let me know which adapter works best and which application to use. I do not need microphone input. Your help is greatly appreciated!

  • newc

    I would really LOVE to use the faber acoustical audio measurement software on my 3gs iphone. But only if I can use the higher audio quality available via the dock connector. I want to be able to plug a decent mic into the dock connector. Sounds simple enough, but I have spent too many dollars already experimenting with connectors, adapters, and various dock connector mic “solutions” (Belkin for example) but I have found no combination that is reliable. I’ve spent hours upon hours researching this trying to find a good off the shelf REASONABLY PRICED product or even to find a satisfactory DIY solution. Personally I’m not spending several hundred dollars for a mic adapter that only works on my iphone, which may or may not be around in 2 years. So I give up (funny I say that but here I am back on this site hoping for solutions). If Faber or any of their competitors want to sell me their products they will have to be more helpful and either encourage someone to build a decent reasonably priced dock connector/mic or have it built. Either that or post a YouTube that shows how to use an OTS adapter with a decent electret mic.

  • Bill

    These are the issues I’m also having. What is needed here is a clearly illustrated signal flow plan that’s written into the APP by the manufacturer as well as pin outs and connection suggestion diagrams. It seems obvious to me that an app designed for spectrum analysis (Sig Scop Pro) would expect customers who want direct input to the software can easily find and determine a very easy approach to that end. Personally, I have not found such a document (drawing or diagram) here but hopefully I will. If so, my comments here are nonsecutur. But otherwise, please take my comments as a suggestion to provide such diagrams and documents to accompany a good product this promises to be. I appologize if the diagrams are, in fact, available on this site but as yet undiscovered. I submit this comment with good intention after having the app for a few days, placed an order for a $40 docking A/V cable but can’t even determine if, upon arrival, this approach to get a direct signal input to the app will be successful (without internal microphone pickup). Best regards, Bill

  • Rick

    I would have to assume that you get requests about newer audio devices that become available to the iOS platform. I recenly ppurchased the Apogee Jam, and would like to get your opinion on it some day. I know the Jam does work with SignalScope as I have tried it.
    It is an input device only and is designed to work directly with a guitar; however, the basic principle is still an A/D with possibly a h/p filter on the front end.

    Someday perhaps, you would post info on the Jam in your Dock Audio Accessory Compatiblity list. Possible mention frequency response and distortion measurements.

    Thank you.
    best regards,

  • William Thrash

    Not sure the issue but I cannot get the Alesis ProTrack with an external mic to work on SSPro on my iPhone 4S, whereas it use to work on my 3GS. I also now cannot get it to work on my iPad. Seems that SSPro use to let me choose “External Mic” instead of “Built-In,” but it’s been a year since I used it last???

    The Alesis reads the mic levels, but they will not show on the iPhone or iPad??? Maybe the Alesis dock is toast?

    Any advice? Thanks much …