atcomsystems.ca/forum Forums General General Telephone & Systems Information Disconnect Supervision Problems

Another question of mine just popped into my head- why is there a pound (#) button on a TT phone anyway? If I press it I just get a reorder signal. I know it's used for telco speed dial features on cellular phones, for example, WKRG (news) vans here have small decals that read:

If you see news happening,

DIAL #555

CellularSouth

I know this feature is obviously only accessible to Cell South customers, but why doesn't it work on landlines?

The WKRG people are just assuming that you are in your car behind them and will be using your cell phone to dial that code.

* and # were developed on land line phones to enable callers to have the equivalent of "flexible 11 and 12 keys". Only the machine you called only knew what to do with these keys. Regular phone calls didn't need them.

This was an example of the 1960s getting in touch with tomorrow. Bell Labs saw the phone as being something more than just a device for talking. These keys were (are) used widely when communicating with voice mail, banking services, complaining about your phone bill, etc. today.

Because cell phones require the "send" key to complete a call, the * and # can be included in the number as wild cards. This also means that there isn't the need for the mandatory 7/10-digit format for the called number. What you are seeing are essentially speed dial codes.

These codes on cell service provers are just marketing tools. They are sold by the cell service providers to TV or radio stations. They are making themselves easier to reach than expecting a caller to jot down a phone number while driving. A few simple digits will result in an immediate call, whereas if you have to actually write down/remember a full number, you might not. They pay for the call, similar to dialing someone collect.

These stations are getting a bunch of money in return for this investment. If they are the first to report anything on the news, they get bragging rights when it comes ratings and award time. That is a coveted accomplishment in their industry.

telecom guy10, hats off to you for taking the time to read older posts! A confession: At least half of what I know about telecom was learned by reading Ed's (and others) posts. There is a vast wealth of knowledge on this forum - the membership is about to reach 30,000 any day now. Thats a big WOW when you consider that the majority of members are real telecom professionals in the US and Canada. I think every state and province is represented here.

Now, on the topic of your particular issue: You mentioned that you doubt there is anything wrong with the 500 sets because you didn't have this problem at your old house. Actually, that doesn't really tell you much, because 1.) The capacitors have aged since then, and aging is what usually causes the problem Ed is talking about; 2.) The loop current and/or off-hook voltage could be higher at your new place (are these POTS lines?); and 3.) A spike could have "punched through" the dielectric in one of the caps recently, making it (electrically) leaky. This last one is unlikely, but possible.

The other thing to remember about the problem Ed is describing is that you don't need to actually be using the phone with the bad capacitor for this to happen. The ringer and capacitor are bridged across the line all the time, so if this happens when using your new cordless phone that still doesn't rule out one of the caps in the 500 sets as the culprit.

Good luck to you in your endeavors!

Jim
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Signature lines are currently on back-order. We apologize for any inconvenience this may cause.

Early DTMF (TT) phones only had 10 buttons on them. Each tone signal is actually a combination of TWO tones, one vertical and one horizontal. To explain:

The first horizontal row of keys (1,2,3) has the frequency of 697 hz. The second horizontal row (4,5,6) has the frequency of 770 hz. For 7,8,9 the freq is 852. For *,0,# the freq is 941.

The first vertical row (1,4,7,*) is 1209, 2,5,8,0 is 1336 and 3,6,9,# is 1477.

When you push the digit "1" you send a combination if 697 hz and 1209 hz. This use of the combination of two tones was done to prevent accidental dialing while talking. Because the tones exist in the realm of human speech it is possible for the human voice to recreate them, combining two distinct tones minimizes this effect (though it is still possible and still happens more often then you would think).

When Western Electric produced the first 10 digit tone dial they realized that they had created, as Ed said, a "free" 11th and 12th key. The tones were already there for them, it was just a question of putting the buttons in place.

The keys were not used much originally. I remember a Johnny Carson monologue on the Tonight Show where he compared the * and # buttons to a man's nipples - nice to play with but completely useless.

Early on PBX manufacturers used them for features (dial * for Call Pickup and # for Call forwarding) or used them as Central Offices do now, as primary digits for features (*69, *72 etc.) In a large plant it was very handy to have an extra set of digits - You already lost 0 for the Operator and 9 for Outside Lines. 8 was often taken up by Paging or LD Trunk access and your extensions often took up some or all of the other available digits. Having * and # available for features was very handy.

Sam

Wow you guys know your stuff! Well when I get a chance I will post about my non-ringing Stromberg-Carlson wall phone... I'm thinking it's something with the capacitor. Anyway thanks everyone!

And to add to Sam's post:
DTMF stands for Dual Tone Multi-Frequency

and now you know.

Don't forget about tha A,B,C&D keys

You mean FO, F, I and P?

And the Autovon keys!

https://en.wikipedia.org/wiki/Dual-tone_multi-frequency

Read and learn your ABCD's