Murray Leinster's "Sam, This is You" (short story, humor, free): Girlfriend trouble due to cross-time talking!

Sam Yoder, a telephone lineman, has been building a hacking gadget: to make private calls over a "party-line". While his gadget won't let him do this, it lets him do something else instead: it lets him talk to himself 10 days in future! Or in past!

That's useful ability, e.g., to make money from betting. That can also land him in trouble with girlfriend!

See also.

1.  C L Moore's "Greater Than Gods" also features a cross-time communicator. A man's two potential descendants from far future are each canvassing to make him marry a particular woman, one that will enable the respective descendant's existence! One of them is even prepared to kill this remote ancestor over the com link if he doesn't choose the right woman! (Hugo Gernsback's "The Killing Flash" (download) involves use of ordinary landline phone network as a murder weapon.)

Fact sheet.

First published: Galaxy, May 1955.
Download full text from Project Gutenberg, Manybooks.
Download old XMinus radio adaptation from Internet Archive.
Rating: A.
Related: Stories of Murray Leinster, from 1950s.