Using the Talk button

Ever wanted to use the phone's green Talk key (sometimes called the Send button) in your application?  You can, but the docs are pretty well hidden, so I thought I'd point them out:

Basically, your app sends a SHCMBM_OVERRIDEKEY message, once, to its own menu bar telling it "When the user presses the Talk button (when my app is foreground) I want to recieve that as a WM_HOTKEY from now on."

Obviously, the most common use for this is to initiate a phone call to a specific number from within your app (using PhoneMakeCall()).   I wouldn't recommend using it for something non-phone-related.

On Smartphone, you can also override some of the other hardware buttons like Volume Up and Down.

- Jason Fuller

Comments (14)

  1. David says:

    Is there a way for a developer to force the speakerphone on during a call? The common request on sites like the pdaphonehome forums is for the speakerphone to be triggered by a physical button press. To rephrase this, could someone write a program that is assigned to a button that forces the speakerphone to toggle during a phone call.


  2. Lutz says:

    That is already standard functionality. While in a call, press and hold the call button – this will toggle the speakerphone on and off.

  3. David says:

    Boy, I wish I could edit that other post. I have no idea what I was thinking. I meant to ask if there was a way to MUTE the call. Again, I have no idea why I wrote about the speakerphone.


    Can we assign Mute to a button…


  4. Paul says:


    how can I catch the red and green phone buttons on a Pocket PC Phone (WM5.0) system wide?

    Why – because I am writing my own phone app to replace the default.



  5. Hi_Jack says:

    It seems that if SHCMBM_OVERRIDEKEY sent in a called process ,it did nothing.

    What do you think about this,dear everyone?

  6. Jing-Hwa Liang says:

    Application must include aygshell.lib

    to use SHCMBM_OVERRIDEKEY, but license fee for each smartphone is US$16 when using aygshell.lib. If you license a core version without aygshell.lib only costs you US$3.0.

    My problem is: How can I get the

    green talk key using core version?

  7. Brien says:

    I’d love to see an example of this posted.  I can’t find a single working example online.

  8. lepton says:

    Is this a C++ only thing or is there a way to trap the talk key in C#?

  9. ppcinfo says:

    I’d like to get notification for the Red button in my application as well. If anyone knows how to do this, please let me know!


  10. dev_cdd says:

    You can read this russian forum with my answer (with code).

  11. imranbaig says:

    On WM 5

    Use Following:

    HWND wnd =  ((CMainFrame*)AfxGetMainWnd())->m_wndCommandBar.m_hWnd;

    ::SendMessage (wnd, SHCMBM_OVERRIDEKEY, VK_TTALK,


                            SHMBOF_NODEFAULT | SHMBOF_NOTIFY));

  12. Cs says:

    Other than the example that imranbaig given, anyone have another? I cannot understand it. Sorry.

  13. dalton says:

    How can I cath the RED button(VK_TEND) in my application?

  14. Chunyuan says:

    how come if i have a full screen application without menubar?

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