Creo entender que quieres saber formas de conectar con Firebird desde cófigo.
Código Delphi
[-]procedure TDMMain.Conectar;
var
oIni: TIniFile;
begin
oIni := TIniFile.Create('MiPrograma.ini');
with DBMain do begin
if (DefaultTransaction.InTransaction) then
DefaultTransaction.Commit;
if Connected then
Close;
DataBaseName := oIni.ReadString('Datos', 'BaseDeDatos', '');
Params.Clear;
Params.Add('user_name=SYSDBA');
Params.Add('password=masterkey');
Open;
DefaultTransaction.StartTransaction;
end;
oIni.Free;
end;