I was thinking how cell phones have no dial tone (to the best of my knowledge), and cell phones work just fine. Sure, a little graphic symbol tells me the strength of the signal, but so could a phone on a land line.
So, is the dial tone obselete? And, how much energy does it waste the phone company, anyway? - Jinx
The dial tone tells you that the CO is connected & listening for your inputs (pulses or tones). It isn’t on the line when the phone is on-hook.
The CO pushes power to the phone to operate it when off-hook. The dial tone is simply an audible component of that power. The total talk-power consumption is trivial over the life of a call, and hte dial tone is a microscopic fraction of that triviality.
Yes, a wired phone could have a display and a computer & a bunch of other stuff to interpret teh line condistions to drive a display to show you it’s OK to dial. that would be lots more complex and consume a lot more power.
Now a lot of feature-rich modern landline instruments have a wall-wart to provide drive all the fancy features. The actual dialing & talking part are powered by the CO & stil work in a power failure. Teh fancy features (and sometimes the ringer) all die if your local power goes out.
In short, replacing the dial tone would increase cost, reduce reliability and increase complexity. Spingears would love it.
Sounds like every American CEO’s wet dream! 
I do!
I do indeed!
Most phones with caller ID built in will let you dial the number, then hit the Talk button–just like a cell phone does. I hardly ever listen for a dial tone anymore at all.
I’m confused by your question, I think. Are you asking how it is that cell phones work without a dial tone? The little visual signal telling you the strength is the equivalent of a dial tone, it just means that the company is ready to receive and transmit your call.
Other than that possible question, LSL Guy has the good answer. If it ain’t broke, don’t fix it.
It’s not just the Americans! If you can come up with a retort like that, you will love the review in today’s NY Times of the new Mercedes “S” class. Read all the way through. It gets good at the end.
I apologize for the hijack.
The dial tone is an artifact derived from POTS (Plain Old Telephone Service), which hasn’t changed much since the 1880’s. And that’s why your old standard phone, even the rotary dial one, works when plugged into any line.
For a POTS line, the dial tone is supplied for humans to know when the equipment on the other end is ready to receive instructions. It’s rare, yes, but under extremently adverse conditions like stormy weather with a high volume of calls and lines down, I have had to wait for a few seconds to get the dial tone.
The dial tone is also detected as a “Ready to Receive” signal by modem circuits. If they don’t get it, they won’t start dialing.
A celphone is a different animal. When you turn it on, it does not immediately connect to the telephone CO (Central Office). It stores the numbers you enter internally, then sends them to the nearest tower all at once when you hit “send.” This is called a “store and forward system.” At the tower, they are re-transmitted thru POTS lines or even something more direct.
A POTS line acts on each number in sequence, so you can’t “back up” and erase with a classic phone. If you make a mistake, you have to hang up and start again. A celphone, since it is a store & forward system, allows for editing the number sequence before re-transmitting it all at once. If you have a fairly new non-cel phone, as Kiminy describes, it also has an internal store & forward system.
If the entire wired phone system were changed, it might make a lot of old phones useless, and a lot of people still use them.
Yeah, and I happen to like the “old fashioned” dial tone. Besides, what 's the big deal? It gives you an acknowledgement that the system is ready, willing, and able. What’s not to like about that? If you got rid of it, you’d just have to come up with some other gimcrack or geegaw to serve as it’s function. It’s intuitive and well known, not an artifac of an earlier era. If it ain’t broke, don’t fix it. Personally, I don’t care for the “dead air” you get on a cell phone, although I understand why it is so.
BTW, did you ever have someone pick up the phone on the other end even though it didn’t seem to ring on your end, but they swear it did? The reason for that is because the “ringing” you hear isn’t their actual phone, it’s merely a continuous recording that everyone hears when they are calling someone. The rings you hear are not synchronized with the rings at the other end, so if they are quick to answer it can seem that the phone did not appear to ring at all.
In the very old days, prior to electronic, computerized switches, The dials tone and busy signals were the output from dedicated alternators in the central offices. I toured one once as a teenager. (a friend of my dad worked there)
In my recollection, this alternator was about the size of a 5-10 HP motor, driven by a similarly sized electric motor. There were two, so one could be taken off line to replace the brushes, etc.
Anyway, I guess the alternator could supply about 5000 W if enough phones were off the hook. Of course if none were off the hook, there would be little load on the motor, so of course the draw would be greatly reduced. I’d WAG average power was around 1000W.
This was a larhe CO, that served the city of Grand Junction, CO in the 1970’s (But not orchard mesa, fruita, etc.) which probably meant about 100,000 people, or 30,000 phone sets.
So on average, I estimate that having dial and busy tones availabe required about 1/30 W per phone line. Or about 1WH per day, or about 1KWH every 3 years.
At$.10/KWH, that means that the average phone user had to spend a whoppinga 3 cents per year for the frivolous tones.
Ummm…why? 