Brain-Computer Interface: In the Federation a brain implant with audio-visual overlays and wireless capability in the microwave range (but not radio) is generally taken for granted, with the exception of telepaths as the sensors break their quantum entanglement with their kin. These implants have varying capabilities by model, but in general they are capable of doing practically everything that a pre-diaspora smartphone could do: communication, gaming, recording, etc.
The recording function is one of the most important to an immortal civilization, when the parahuman brain runs short of available memory it can use some reinforcement. It can even record complete memories from the brain, but those are only usable in their complete state by the same user who first recorded as each brain is different. The exception being bioprinted copies.
There are also a number of Outworlds who have maintained enough technology to use their own versions of the BCI, the most notable being the Emilia Collective.