If the ALD system you plan on using has a normal headphone jack, that should be all you would need. I've seen many ALD systems that are one piece infrared system which are not able to be patched. They have no headphone jack on them. The kind of system depends on the venue.
Just be informed that these systems are meant for the hearing impaired, that their tone, balance, and mix may not be conducive to taping, and that reception depending on your location in the venue may be static filled, and difficult to maintain for the duration of the event.