How come cell phones don't have dial tones?

[underpants]

Are dial tones to be a thing of the past some time soon?

Just wondering.

[kay1864]

1. Dunno for sure, but I'm guessing it's because

with a landline phone, it's either working or it's not. With a cell phone, your signal strength varies, which a dial tone wouldn't tell you very well.

Plus with a cell, it was designed that you hit Send after you've dialed the number. I'm guessing that design was b/c it's easier to misdial with a cell, so you're supposed to look at the number you entered.

[LaraMN]

2. More importantly,

who's the weirdo who keeps texting me, "who this?"

[underpants]

3. Good question

and yet still we have no answers

[LaraMN]

4. Yeah- or the one who sent me

a "love-o-gram" at my school email addy.
I thought it was my husband.
Wrong.

:scared:

[Deja Q]

5. I'm hum in your ear when you whip out your big cell phone...

Will that help? O8)

[tigereye]

6. aren't dial tones a function of the old-school phone company

and it's hardware?

I would guess that cell phones aren't part of that, hence no dial tones.


Interesting question...

[underpants]

7. That's why I am here

ACtually now that you mention it (this comes from WAY back in the catacombs of the mind) I saw a guy with a tape recorder on TV a long time ago dialing a phone by playing a recording of the dialed numbers into the handset. Apparently phones just listen for the sound of each number and call from there. Okay maybe that isn't correct but it was fun while it lasted.

[Solon]

9. You're referring to Phreaking...

He wasn't dialing in the numbers, but rather the change for a public payphone. Payphones, if you listen while you insert change, make a series of beeps depending on the coin you insert into the phone. There's a sound for a Quarter, a Nickle, and a Dime. Anyways, you can record these tones, and play them back through the mouthpiece, and basically call anyone around the world for free. Granted, this depends on the quality of the recording/playback device, dictation machines suck, MP3 players are perfect, you can download the tones, and they are high quality.

The only problem is this, its illegal, and it best works on older phone systems. Nowadays, its almost impossible to do this technique, used to work in the past, but with digital switching, etc. its becoming much harder.

[madinmaryland]

8. It is a function of the telephone companies.

Basically it was a low voltage sent over the lines, which produces the the dial-tone hum you are familiar with. This was a quick way to tell if you had connectivity to the Central Office.

With cell-phone you can't send transmit in this fassion. To check for connectivity, most cell-phone indicate if they are receiving a signal via a bar-graph.

[BigMcLargehuge]

10. I can answer this!

Direct Connection between Home and Central Office

Dial tone is a service delivered over copper landlines from the Telco Central Office (CO). Dial Tone is a "switch based service". Modern wired phone systems routinely use both digital transmission and a mix of copper and fiber infrastructure so the act of "receiving dial tone" is a little different than in the past age of analog telephony. Modern dial tone over a wired system uses a series of digital signals to inform the switch that the telephone (station) is off-hook. These signals are carried "out of band" in the D-Channel in L-DAP/ISDN based implementation and "in-band" in DSL and FDM implementations.

Digital stations receive a "play dial tone" code from the CO rather than direct current from the CO in a digital system.

Indirect Connection between Home and Central Office via a Remote Digital Terminal

Signals are carried in analog format to the Remote Terminal (RT), where the actual request for service signal is sent on to the CO. However many manufacturers of Remote Terminal equipment make dial tone provision a feature of their products. Thus, receiving dial tone from the RT is the same as it would be if you were receiving dial tone from the CO itself.

Indirect Connection between Home and Central Office via Fiber to the Premesis/B-PON architecture

In Fiber To The Premesis implementations the request for dial tone is converted into a digital optical signal at the pump laser attached to the Terminal Box attached to the side of your house. And the battery in the Terminal Box equipment sends the low voltage signal to the station.

Connection between a Mobile Handset and the Base Station

Wireless networks, such as PCS or Digital Cellular do not maintain a physical connection to the switching offices (known as MCDs in Wireless). Instead of going "off-hook" like a landline phone, the handset powers up and begin exchanging messages with the base station over the control channel. These messages set up the connection between the handset and the MCD. Connection is signaled visually in CDMA systems, and both visually and with dial tone in TDMA systems (since TDMA systems use a specifically assigned timeslot within a channel for upstream and downstream traffic)