AFAIK every "IFR GPS" has the same data entry method, using the two concentric rotary buttons. One moves the cursor and the other selects the character A-Z, 0-9 etc.
The characters presented are, I believe, limited to actual identifiers so if you are entering the last char of say ORTAC and you are on ORTAA and there is no ORTAB in the database then the next character presented after the A will be C and not B.
The G1000 has the exceedingly desirable FMS-style keypad entry option but only Lancair (
AFAIK) has offered this.