# Old timey movie trope where somebody frantically jiggles the phone hook--what was that about?

**URL:** <https://boards.straightdope.com/t/old-timey-movie-trope-where-somebody-frantically-jiggles-the-phone-hook-what-was-that-about/831534>\
**Category:** Factual Questions\
**Created:** [March 25, 2019, 11:47pm UTC](https://boards.straightdope.com/t/old-timey-movie-trope-where-somebody-frantically-jiggles-the-phone-hook-what-was-that-about/831534 "2019-03-25T23:47:13Z")\
**Posts on this page:** 1\
**Page:** 2

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**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\
**Post date:** [March 27, 2019, 5:40pm UTC](https://boards.straightdope.com/t/old-timey-movie-trope-where-somebody-frantically-jiggles-the-phone-hook-what-was-that-about/831534/21 "2019-03-27T17:40:41Z")

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> [@Mr\_Downtown](#):
>
> Crossbar is a _newer_ kind than Strowger; it’s just that there’s now an _even newer_ kind.

Yes, and Strowger was the first automated switching system.

> [@](#):
>
> But nearly all ESS exchanges had a pulse converter, meaning it would work nearly anywhere until maybe a decade ago—and probably still works most places.

Pulse dialing doesn’t work anymore? Do the phone companies still charge more for DTMF service?

> [@Hilarity\_N.Suze](#):
>
> Nope, you’re going to be dialing it the same way.

I mentioned two different ways to dial a phone: DTMF and pulse. You’re going to need to be more clear.

> [@](#):
>
> People whose lines connected to a step dialer could not have a touchtone phone, and sometimes it was the installer who had to tell them that. I guess in theory we were also supposed to explain why. But it wasn’t something on the phone, it was something in the CO. Basically, if your exchange number was 365 (for example) you would be going through a step dialer and you couldn’t have touchtone but the house next door might have a 321 exchange number and they could have a touchtone. And both these systems were in the same CO, although by the time I worked there some of the COs in Denver had only the newer systems. Mine, however, also had the old step systems.

Right. To have DTMF, you need a system which can decode the frequencies and make decisions based on that, not an old electromechanical system driven by pulses in the line voltage induced by a rotary dial or jiggling the handle.

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