Before cellphones, which devices were used to send digital messages?

little b, it's pager

I've not used a Paget's

Pagers are still used (notably Lebanon's terrorist organisation Hezbollah for secure communications due to Israel's potential infiltration into cellphones) (I don't think it's just Hezbollah here)

Wowser. I haven’t seen a pager in years lol.

doctors in hospitals use them

paging dr. pepper