[gnicholas]

Yeah that surprised me too. Is it there so that when the finger stop moves, it registers the number? I've only had a few rotary phones in my life, but I've never seen one where that doohickey (which I believe is the technical term) moves.

[Animats]

The moving finger stop was a feature of the Trimline dial phone.[1] It allows making the dial slightly smaller. On most dial phones, there's a large gap between the 1 and 0 holes. On Trimlines, and this new thing, there is no gap. Without that moving finger stop, you get a dial handset like this AT&T prototype: [2] That was called "the Schmoo".[3] Huge bulge in the middle of the handset.

The moving finger stop also appeared in 1960s versions of the Lineman's Test Set (the "butt set", usually hung from a tool belt), where the dial was on the back of the earpiece.

[1] https://en.wikipedia.org/wiki/Trimline_telephone

[2] https://www.bellsystemmemorial.com/images/dl/misc/schmoo.jpg

[3] https://www.bellsystemmemorial.com/telephones-trimline-artic...

[jonah-archive]

etymologically, the term Schmoo or Shmoo (typically based on the characteristic shape) originates with the cartoon character popularized by Al Capp: https://en.wikipedia.org/wiki/Shmoo

A favorite example is the shape of a budding haploid yeast cell, known in the literature as a shmoo (though as that wikipedia page will indicate, there are a lot of other delightful schmoo/shmoo eponyms): https://web.archive.org/web/20071111122821/http://discoverma...

[someweirdperson]

> Is it there so that when the finger stop moves, it registers the number?

No. Moving to the stop is just to wind up the mechanism up to a defined point. After being released the dial turns back at a defined speed, and creates a number short on-hook spikes, depending on far it has been wound up - the number to be dialed.

It's possible to quickly tap the hook to dial a number, too. It's easy for low numbers, but the dial helps the slow ones of us to tap exactly 9 clicks in the defined time to dial a 9.

No idea if that un-smartphone works exactly like the real thing.

[Johnythree]

If memory serves, the gap on the dial set the "interdial pause" which created a minimum gap between strings of digits, which gave sufficient time for the exchange equipment to switch to the next selector..