If you have two keyboards added to your project then the user will be able to swipe between them. If you want to have a button on the keypad for toggling you can alternatively take advantage of the SHIFT modifier to have two separate keypads toggled by the shift key code. Most applications don't require lower and upper case alphas so you might be able to get away with a SHIFT key to toggle between capital alphas and numeric keys. The problem with this approach is that you have to maintain the same key lay out for both keypads.
There is a workaround that I figured out that uses the macro call to a script for toggling a different keypad and it seems to work:
Re: Can someone please help me create a custom keyboard like in iphone? Where we can just tap the number sign in the main alphabet keyboard instead of swiping it? I don't know what's the value for numeric press like the upper/shift.
You may even be able to then map a physical button like the PTT button on the TC8000s handle in order to toggle between keypads.