I have yamaha p115 piano with hamme r action it has only has usb midi interface. I wanna use it with yamaha montage 6. How can i connect it to yamaha montage with usb cable ??
Montage does not accept directly connecting USB-only keyboards to it. So I'll start by answering what NOT to do: don't plug a USB cable directly between Montage and your P115.
What you need to do is place a computer between the two. Something that will manage routing the USB MIDI between the two devices. Tablets with hubs can even be used for this assuming you have the right software (Cubasis for iOS, Camelot Pro for iOS/Android/Windows Surface, Cubase or other - even free DAW or standalone for PC). When it comes to computers (including tablets) - there are tons of software options for what will work. Some have more features than others but you may not need much. Some have very few features but could be difficult to setup (like MIDI pipes or virtual MIDI ports with links between).
It may help to know, now you know you need a computer of some sort - what you'd plan on using for this task. Because there are different options depending on the environment (iOS, MacOS, Windows, Android, etc).
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R
There are small devices that take USB-MIDI In and convert that to 5-pin MIDI Out and vice versa, that are not computers, laptops or tablets.
Google
USB-MIDI to MIDI converter