Intertemporal Communication?

Is just communication, as opposed to bodily travel, between times conceivable? The only good point in Robert Heinlein's Time Enough For Love is that Lazarus Long, Time Traveller, devises a clever way to post a letter from 1916 to his family thousands of years later. Jack Finney, the master of nostalgic time travel fiction, wrote a short story in which a letter with an old style stamp on the envelope is posted in a defunct post office and was received decades earlier when that post office was still open. But Long communicates only futurewards and Finney's story is fantasy, not sf.

We should consider:

The Time Machine by HG Wells

The Time Patrol series by Poul Anderson

Starfarers by Poul Anderson

"Beep"/The Quincunx Of Time by James Blish

There is no intertemporal communication in The Time Machine? Sure. But there is a tabletop model Time Machine which is sent into the past or the future, the Time Traveller is not sure which. That strikes me as a precursor of the small desktop message shuttles used by Anderson's Time Patrollers. They must send typed messages. They cannot speak to other times. That happens in the remaining two works listed above. Onward then.