Not sure which bridge you are using but all Polycom bridges would only require DTMF numbers for an access code. There is no need for the keyboard. The keyboard is available for placing a call to an E.164 address etc.
Thanks. I am using sometimes a bridge with a CAFE room for testing and I did not know its number (9999#) so I wanted to use remote controls to browse the list (arrows) but of course they are nowhere to be seen on the iPad user interface ! Now I found the number.