Need help reading ring generator circuit

**Crashless** · 02-15-2005, 01:59 AM

I'm planning a carputer based around an old laptop with WOR. I've taken a look at a lot of the options to remotely turn it on, and the easiest option I think I have is to build a phone ring generator, and just plug it into the modem port when I dock my laptop in the car.

I'm not interested in a docking station, and I don't want to open up my laptop and solder. I want to find a solution that can be upgraded with my laptop. IE: setup a touchscreen, DC power source, wifi antenna, gps mouse, and this WOR 'switch'.

I believe I found a circuit diagram that can do what I want. Basically I'm imagining a switch that triggers this black box, which in turn triggers the WOR circuit of the laptop.

Now I haven't looked at circuit diagrams since 8th grade, so I can only understand this diagram at a basic level.

diagram here

I like the 9V solution because I don't have to run more wires around to my car circuit. I could just run 6 D cells in series, put it in a tupperware, hide it somewhere and call it a day.

Now my questions, as it's my first homebrew circuit:

1. will any blank circuit board (ala ratshack) work as a base?
2. Where's the negative side of the 9V source hookup?
3. what's with the 120V part, on the right side?
4. what does the curly q mean, next to the +9V? An inductor? why?
5. all those capacitors are grounded...but to what?
6. all those NOT logic gates (inverters?) have numbers in them, what do they mean?
7. what does it mean to have an arrow to the 50k resistor on the bottom-left?
8. is that gap, with the sideways 'T' on the top-left where the push-switch goes?
9. am I in over my head? Is this way to hard for a noob? etc, etc...

Thanks in advance.

**Nic** · 02-15-2005, 02:48 AM

1. its probably easy to use one of those solderless boards
2. ground
3. "The telephone ring generator shown below generates the needed high voltage from a simple switching mode power supply"
4. if you mean the thing next to 10mH thats an inductor
5. see #2
6. pretty sure they are pin numbers the ones outside are part numbers
7. thats a variable resistor
8. yes
9. possibly, but its not like those parts are gonna be super expensive so if u screw up it dosent really matter

**anorth_uk** · 02-15-2005, 02:50 AM

Hi,

hope this helps

1. will any blank circuit board (ala ratshack) work as a base? Should do
2. Where's the negative side of the 9V source hookup?the ground symbols are your negative rail
3. what's with the 120V part, on the right side?Don't know, but could be the induced voltage from the inductor
4. what does the curly q mean, next to the +9V? An inductor? why?
5. all those capacitors are grounded...but to what?Thats the negative rail of your supply
6. all those NOT logic gates (inverters?) have numbers in them, what do they mean?They are the pin numbers
7. what does it mean to have an arrow to the 50k resistor on the bottom-left?That is the symbol for a variable or preset resistor
8. is that gap, with the sideways 'T' on the top-left where the push-switch goes?that is the symbol for a momentary push to make switch
9. am I in over my head? Is this way to hard for a noob? etc, etc...That is for you to work out, but it shouldn't be too hard

Squiff

**Nic** · 02-15-2005, 02:54 AM

err now that i look at it this circuit might generate the actually ringing, not the ringing signal, i'm not sure i'd be comfortable hooking 120v up to my computer to find out :P

**Nic** · 02-15-2005, 03:03 AM

hmm maybe not "The telephone company sends a ringing signal which is an AC waveform. Although the common frequency used in the United States is 20 HZ and in Europe is typically 25 Hz, it can be any frequency between 15 and 68 Hz. Most of the world uses frequencies between 20 and 40 Hz. The voltage at the subscribers end depends upon loop length and number of ringers attached to the line; it could be between 40 and 150 Volts."

**anorth_uk** · 02-15-2005, 03:17 AM

I think you are right, the write up of the circuit states it produces the high voltage, not sure this is a good circuit to have anywhere near a pc of any description

**Dexter** · 02-15-2005, 04:32 AM

those "logic gates" are op amps...

**Crashless** · 02-15-2005, 03:40 PM

For the record, if I can pull it off, the first test will most definitly NOT be hooked up to my computer. I plan on recruiting an old crappy phone to be the guinea pig.

All the help has been great. I guess I'll be going to rat shack soon. I'll post pics etc when I get to it.

Thanks for all the help.

**davesaudio2** · 02-21-2005, 05:43 PM

-just speculating-it may be interesting to see if you have a rs232 port and if the "ring indicator" lead can trigger the same "wake". voltages would be alittle friendlier...