# A light on the phone blinks when I have a voicemail. How?

**URL:** <https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452>\
**Category:** Factual Questions\
**Created:** [September 17, 2000, 3:03am UTC](https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452 "2000-09-17T03:03:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![troub](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troub/32/14802_2.png) [@troub](https://boards.straightdope.com/u/troub)\
**Post date:** [September 17, 2000, 3:03am UTC](https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452/1 "2000-09-17T03:03:28Z")

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This is kind of a silly question, but it’s bothered me for days. How exactly does the phone know that there is a message waiting for me? Is there a special signal or voltage sent down the line that signifies this? Does it have something to do with the broken dial tone when there is a message waiting? Are the broken dial tone and this special signal (if it exists) related? I would greatly appreciate the straght dope from any telecom gurus out there.

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**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\
**Post date:** [September 17, 2000, 4:14am UTC](https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452/2 "2000-09-17T04:14:37Z")

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A good question - my phone does this as well, and I would really like to know the answer myself. Guys?

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**Author:** ![Enright3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/enright3/32/2897_2.png) [@Enright3](https://boards.straightdope.com/u/Enright3)\
**Post date:** [September 17, 2000, 4:42am UTC](https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452/3 "2000-09-17T04:42:04Z")

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Does your phone have a “stuttering” dial tone when you have messages? (I guess the first question is: Are you using the phone company for voice mail?)

I use Bellsouth’s voicemail system, and when I have a message waiting, my dial tone ‘stutters’ when I first pick up the phone. My callerID also blinks when I have messages. The way my callerID know I have messages, is because every five minutes or so in internally picks up my phone and ‘listens’ for that stuttering dial tone.

Hope that helps…

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**Author:** ![troub](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troub/32/14802_2.png) [@troub](https://boards.straightdope.com/u/troub)\
**Post date:** [September 17, 2000, 5:23am UTC](https://boards.straightdope.com/t/a-light-on-the-phone-blinks-when-i-have-a-voicemail-how/33452/4 "2000-09-17T05:23:38Z")

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Yes, I use the phone company for voicemail and I have a stuttering dial tone when I have messages.

> [@](#):
>
> \*Originally posted by Enright3 \*  
> \*\*The way my callerID know I have messages, is because every five minutes or so in internally picks up my phone and ‘listens’ for that stuttering dial tone.  
> \*\*

This is what I though it might do–I was just curious because it would seem to be the easiest solution, yet rather inelegant to have to open the phone line every few minutes.