if it looks like this, it's a 6-20. It's a 20 amp 220 plug. Common for window heater/ac units.
http://www.homedepot.com/catalog/productImages/1000/10/10dbd6ee-3725-43b9-8c30-eb4ce031f032_1000.jpg
You'll just need an EVSE with adapter to 6-20 or one already equipped with the 6-20 plug.
http://www.homedepot.com/catalog/productImages/1000/10/10dbd6ee-3725-43b9-8c30-eb4ce031f032_1000.jpg
You'll just need an EVSE with adapter to 6-20 or one already equipped with the 6-20 plug.