Information on ensuring accessibility
Here is a general primer written by Mel Chua on event access for d/Deaf and hard-of-hearing (DHH) people, and the first big point is that everyone is different, and you should ask each individual DHH person what they need. For me specifically, though -- here's how I'd answer that.
Schedules/notes/documentation/papers in written form whenever they are available. Interpreters and captioners will need them for prep as well, so please pass those on!
ASL (American Sign Language) interpretation
If ASL interpretation is needed for a 1+ hour event, it will be required to have a team for the duration of the event/conference, including evening networking events; teams of two or more will rotate periodically in order to prevent fatigue from affecting interpreting quality. Not all interpreters can handle all scenarios -- so make sure the interpreting team can handle this level of event. I may be able to connect you to either locals who are well qualified, or interpreters who've worked with me in the past. For more information, see: interpreter prep letter.
CART (realtime transcription)
CART is realtime stenographic transcription. CART can function on a time delay, interfering access to actively engage. If in-person CART is not available, remote CART with a projected screen is doable though usually much less accurate. As a side benefit, other attendees with hearing loss, ADHD, dyslexia, auditory processing disorder, and English-language learners will benefit -- and you'll have transcripts of the keynotes/plenaries immediately afterwards.
For other DHH folks: tips on requesting
I'm working on making my templates for access requests into resources that would be useful to others. One early version of this is a breakdown of how I send in a request for interpreting to a new person/event if I want to include a lot of detail. My approach is particular to who I am and the position I'm in, so my letter may or may not work for you -- adapt it to your own situation as needed!
Credit to Mel Chua for publishing a page that I used as a template. Mel, if you ever come across this page, I owe you coffee in gratitude!