"Equal Level Conversion" is a rebid after an opposing takeout double
to show 5-4 shape in the unbid suits. Specifically, it is used after your right-hand opponent ("RHO") opens 1/,
you double, and partner responds 2.
The benefit of Equal Level Conversion is increased bidding flexibility. With a 4-5 hand, you can make a takeout double
with club shortness. The 2
is your outlet bid if partner happens to bid clubs.
The drawback to Equal Level Conversion is that you can no longer play 2
in the above auctions as a strong one-suiter in diamonds. You must jump-rebid 3