China Link

[Brazucs]

Well, maybe not China but definitely somewhere local.

So, why is this not working for me?

[Arcane Wizard]

1) Your phone already has that functionality all on it's own.
2) You need software?

[Tiberious726]

microsoft fears the ti os becuase it know that even it is better than windows and is scrambling your signal

[c_plus_plus]

Ha! good one.

[DigiTan]

(If this isn't a hoax) A cellphone input would be AC-coupled to block any DC from clipping the audio amps. The data would have to be encoded that it never holds the same level for more than a few milliseconds.

[Brazucs]

No hoax... just wondering whether or not it's possible. Basically, I'm asking if you can call someone and link up to them.

[DigiTan]

I guess so. There are a lot of cell model that have modem capabilities. You could probably find software to install a modem program from one of those cell hacker forums--it'd probably be real model-specific though.

[Raster]

cant you just make a tone generator that generates a tone for 10, 01, and 11? And translate it? or something...

[elfprince13]

[Brazucs]

1. The "working" has ceased quite a few years ago, especially with the advent of broadband.
2. You'd wanna carry a modem around with ya?

What about one of those little USB network adapters? Is there any work on that?

[Raster]

[DigiTan]

I guess I could look into this stuff. I found a forum on cell phone hacks from this yesterday, and cell modems seem to be common trick for these guys.

[Fr0stbyte124]

I spent quite a while trying to do that, but I doubt it's possible. The problem lies in the voltages. While it may look like an audio jack, the data port is actutally a stripped-down serial port, complete with 5v signals and hardware logic. A typical headset port can't supply the kind of voltage differences necessary to register on the calculator side.

Still, there would be some hope if you could figure out how to hack the voltage regulator inside the phone. It's connected to whatever circutry that model uses as the dsp, but even if you managed to get code down that deep (I've been unsuccessful with that; cell phones are snobs) you would have to figure out how the regulator is connected and then how to operate it and then find out if it's possible to adjust it enough.

Even worse, the things are a devil to hardware hack, because they use those annoying miniturized all-in-one packages that you can't even begin to understand the pinout of one, because the new chip is proprietary and only exists for that one specific model. (Many models support jtag, or at least the core processors do) I'm not too experienced in this, so maybe there is a better way. I've thought about even piggybacking the signal off another peripheral, but again that would run the issue of just how to get down to the machine code layer. In theory you could flash/flex a driver onto the phone, but I've never met anyone with even a rudimentary idea of how to make one.

I've been working on a Motorola v220, btw. An absolute horid phone two generations behind the market with poor reception and is pointless to hack, as it doesn't even have a decent operating system, and is neigh impossible to unlock without paying for a service. Don't get one if you can help it.


Of course, if you're lucky enough to have a phone with a serial port, then you should have no problem. There a special streaming class in Java specifically for serial ports.

[Rezek]

[DigiTan]

If you place a Schmidt trigger or comparitor between the phone and the calc, it will supply the voltage levels the calc needs to register each bit. Both are extremely small devices that only need 2 inputs and 1 output.

It really only solves one problem because the calc needs to 2 bi-directional ports which is very difficult to get from an audio interface. There's also that deliberate voice echo that is used in GSM phones. If someone had one of this data ports they mention on the forums, it would likely get around the problem. But it would probably require significant hardware and software on the calc end.

[benryves]

There is a reason we use modems and don't directly try to send bits over the phone lines, and this is it. You would need to encode the signals into AC before using the calculator link.
Also, the socket on the bottom of mobile phones (Nokia, at least) have in/out. The calculator uses both data lines as in/out (sending a bit is pull one line low, wait for the other to go low, bring the line high, wait for the other to go high - which line you pull low first corresponds to whether the bit is 1 or 0). The calculator has no reliable timing (at least, not in the basic models) so plain serial I/O wouldn't work.

[Raster]

Well, it is a pretty basic consept on how to do this. The calc has only 2 data lines. So we only have to deal with 3 tones (01, 10, and 11). Each calc has a transmitter and a reciver hooked up to it generating and translating these tones. If both calcs were to transmit data at the same time, it would be a problem with the program on the calc, not the circuit, because the calc can not recive and transmit data at the same time. Im sure you can use the standard DTMF tones to generate this. There are 4 extra tones (recognized as A,B,C,D) that are unused by all phones, and are only used in modems. you can use these tones, with no problems at all.

You can find out how DTMF works here http://en.wikipedia.org/wiki/DTMF
You can use The NTE1690 for your generator
And, I am having a hard time finding a decoder that has not been discontinued...

[Super Speler]

I was thinking about this and realised something. Cell phones have IM capablities. If you can set your calculator up like that not only would you be able to IM but you could also make the phone except sound giving the calculator sound.

[leofox]

You could also just send a text message to your friends. Every phone now a days can do SMS.

[Gottvonallem]

I work with some guys on an WiFi System for the 68Ks.It doesnt work yet but in a half year we are maybe ready and you can make this without an modem or anything like this only with an WLAN-Module which costs 10€ (and its very small 1*2cm)