There's a slightly interesting history to this feature, which should still work on a conventional land line. It was mandated as a partial solution to a scam called "slamming," in which a disreputable long-distance carrier would inform a customer's local exchange carrier that they had 'requested' that their default long distance carrier be changed... without their knowledge.

"Slamming" is not to be confused with "Cramming," another common telephone billing scam of the post-breakup period, because all of these got fun rhyming names.