About Line Simulator

[mautheus]

I talked with a friend about the IC 555 working in astable mode. He told me that it is possible to generate dial tone and in conjunction with other components of a circuit to tell it. This would suficiene for Dreamcast detect line and so must use the Quake III.
It's just an idea I had.
I look forward opinions.

[Favrenation]

From my basic hardware knowledge, that is just a basic clock/timer used for sequential logic. Building a phone line simulator at least just the functionality needed for the dream-cast would require more logic. I'm not even sure if a clock can generate an audible dial tone unless its at a weird frequency. Correct me if I am wrong though.

http://veryuseful.info/linesim/ this is a circuit of a simulator. Not sure if it will help you but it looks like a good way to start.

[mautheus]

I do not think it requires more logic. You remember the swap trick that was done in Quake? I believe that the Dreamcast only need the dial tone. Thus, the IC 555 does. And this simulator line you indicated uses the same IC. Look at the list of components on site.

Next week I'll buy the components and this friend of mine will make the simulator. So I post here as stayed, if really the Dreamcast detected signal line or not.

[Favrenation]

Yeah, I was thinking more of a legit simulator. If you want the pc-dc server to pickup and hangup on its own, then you need to have more logic for that. Just having a dialtone would be cool enough though. I'm interested in hearing more updates on this. I found this if you havnt seen it yet: http://www.reconnsworld.com/audio_tonegenerate.html

EDIT: This seems more useful
http://www.ugcs.caltech.edu/~blacker/hi ... negen.html

[brourke228]

I see a lot of these complicated circuits for building line simulators using discrete analog components. Most of which were from the 90s or earlier. I wonder if it might be hell of a lot easier to use something like a microcontroller instead though. And use a transformer or some amplifiers to up the voltage. I'm not saying all of it could be eliminated but certainly a lot of the logic circuity could be removed.

EDIT: Should have googled this first heh .. http://www.next.gr/microcontrollers/pic ... l7418.html

PICs are fairly easy to work with. That is what a 21st century phone simulator should look like.

[alexsandro]

I see a lot of these complicated circuits for building line simulators using discrete analog components. Most of which were from the 90s or earlier. I wonder if it might be hell of a lot easier to use something like a microcontroller instead though. And use a transformer or some amplifiers to up the voltage. I'm not saying all of it could be eliminated but certainly a lot of the logic circuity could be removed.

EDIT: Should have googled this first heh .. http://www.next.gr/microcontrollers/pic ... l7418.html

PICs are fairly easy to work with. That is what a 21st century phone simulator should look like.

https://www.youtube.com/watch?v=cfAdc1d46FU
https://www.youtube.com/watch?v=_UXAcKFQzDE

[FuzzyFish]

Seeing as we are just trying to generate a dial-tone, and not much else seems like an Arduino board could certainly handle this task.

-Generate two square wave 350 Hz and 440 Hz PWM signals (Euro phones use a single 425Hz tone, not sure if a US modem would recognize this but it would make it way easier. Worth a shot at the least, for simplicity sake)
-Use an RC filter, to round the signal off (Close enough for the modem to at least view it as a valid dial-tone, hopefully).
-External circuitry to mix the two channels.
-Line voltage inducer could also be incorporated into this as well very easily using your power supply
-Some method of disabling the dial-tone soon as a number is dialed, didn't really look into this
-Using the reset button on the Arduino itself could start generating the tone again.


While it's not the most ideal chip to use, it's easily able to be programmed on a DIY level. And not to mention very inexpensive.

[Favrenation]

I was just thinking that maybe a raspberry pi could work. They have GPIO pins that can be used for all sorts of things. Its like an arduino but you can install a full fledged linux distro on it. You could possibly attach a female rj11 port on the gpio pins and use software to emulate a modem. I assume that's not much different than how the cheap win modems work.