Connecting CTK-2550 keyboard to phone ,malfunctions volume button of phone

[Gayathri]

When I connect my phone to the keyboard , it is harming the volume control of my phone. Thereby , not allowing me to control the volume of my phone.

[- T -]

Since the CTK-2500/2550 have no USB connections, I assume that you are trying to connect one of the keyboard's audio connections to your phone.  Which connector on the keyboard are you trying to connect to your phone - the Phones/Output jack or the Audio In jack ?  Are you trying to connect to an iPhone or an Android phone?  If an Android phone, what make and model is it?  The audio jack in some phones is a 4 conductor TRRS (Tip-Ring-Ring-Sleeve) jack instead  of the typical 3 conductor stereo TRS (Tip-Ring-Sleeve) jack.  This is to accomodate headsets that require totally separate circuits for the mic and earphone.

[- T -]

Whatever cable you are using to connect the CTK-2550 to your phone, connect the phone end only, do not connect the keyboard end, and see if your volume control is affected.  In order to protect against hearing damage, some phones and tablets limit the volume when something is connected to the "headphones" jack, but it is the presence of a plug in this jack that initiates the limitation, not the connected device.  Also, whatever app you are using with this connection, start the app without connecting the phone to the CTK-2550 and see if your phone's volume is affected.  If it is, then the problem is the app, not the CTK-2550.  If the CTK-2550 is, in fact, adversely affecting your phone's volume control, then your phone is not compatible with the CTK-2550, and should not be connected to it.  If your phone is an Android device, with all the various "flavors" of the Android OS, there really are no gaurantees of what will work with what.