In terms of communication, most online platforms of teaching and learning are?

Most online teaching and learning platforms are asynchronous, letting learner and teacher engage at different times rather than together in real time.

Recorded lectures, discussion forums, emailed assignments and stored resources are accessed whenever the learner chooses, so presence need not coincide.

Synchronous communication needs both parties online at the same moment, as in a live class, which describes only a part of online learning.

Calling these platforms one to one ignores their reach to large, dispersed groups of learners at once.

Saying they are tied to a specific time frame is the opposite of asynchronous flexibility that defines most such platforms.

Asynchronous design is what allows self paced learning across time zones on modern learning management systems.