A SELECTIVE SWITCH FOR GETTING MORE COMFORTABLE SCANNING written by Dr. Fraud HI PHREAKS, In thiz short article, I will show you an easy possibility to get a more com- fortable way to make BB-calls and scannings. Most of you use one of the fol- lowing ways to call: 1.) U pick up the handset of the phone; you get a dialtone. Then, you dial the number you wish to call. If BOXING fails, you hang up and try it again... 2.) U send a "HIGH" to yout LPT port. This causes a little circuit to open the line. You get a dial tone...and you dial.... Of course, both of these methods are pretty nice...but here`s a better way to get control over your line status: Its possible to control the line with a little switch that always "listens" to your soundcard`s output; if that switch recieves a tone of a certain fre- quency (and you can tell the circuit what frequency this should be), it pro- duces a "HIGH". This can be used to open/close a relais. NOTE: There's a blueprint picturefile with this article, called BB-PLAN.GIF ! Question: Why do I need that circuit ? Answer : Simple. Cause it`s comfortable and easy to use. Okay... before I tell you more of that question/answer rubbish, you should take a look on that phunny plan in that tiny GIF-picture. (BB-PLAN.GIF) First, here are the materials you need to build up the switch: C1= 2,2 uF C2= 47 nF C3= 100 nF C4= 10 nF P = 20 K D = common diod, as e.g. 1N 914 IC= 567 (LM 567, NE 567 etc.) ...costs `bout 1$/piece... You can build this thing any way you want... there are no critical values you must pay attention for. Here are some electrical data: - supply range: 4,75V to 9V - supply current typ: 7 mA - Input resistance: 20K - smallest detectable input: 20mV (!) - highest centre frequency: 500 KHz (!) As you can see, the electrical data allow an universal use of that switch. The resonance-frequency is defined as follows: Fo=1/(P*C4) The band-width is the following: B= sqr(Ue/Fo*C4) ! NOTE: Depends on Ue ! It`s adjustable from 1% up to more than 10%. This means, that, if you adjust it to 1%, a 1000 Hz tone will only be recognized from 990 Hz up to 1010 Hz. If you use 10%, you will be able to send 900 Hz up to 1100 Hz to get a response from the switch. Question: How Do I use that phunny switch ? Answer : Simple. Just connect it via a relais (ca. 5V) to your phone line. The output voltage (pin 4+8) should be used to control the "prima- ry" side. Question: And then ? Answer : Then you only have to move the trimmer until the relays "clicks" when you send the frequency you want. Some dialers (e.g., the latest SCAVENGER dialer) support that. If you wanna get off-hook and on-hook again in an easy way, just connect that device to your soundcard/phone line (Ue) and you will have a great utility to get a phree line within about 2 seconds just by pressing a stupid little key. The relais will stay open as long as that tone is recieved. Note for practical use: If you decide to use that system, you should pay at- tention to the following advices: 1.) The value of P depends on the frequency you wanna use. It`s useful to use (haha...nice english) a frequency that is above the "normal" signalling frequency (e.g. 3900 Hz.) 2.) Depending on that value, the value of the poti can vary... just look for a good frequency, get the correct value and use the correct resistor for the poti. Sometimes, it`s more than 20K. 3.) Avoid interferences. If you don`t, (e.g. you send a 3000/3001 Hz signal), the behavior of the switch will get unstable. In fact, this can be also quite useful (Analyst, u know...), but normally, it`s senseless. 4.) Block your output. Sometimes, you connect your soundcard`s output with any devices without checking whether they are potential-free. This means, that if you connect your soundcard to the phone-line _and_ to that switch, you may get a problem `cause your signal is not potential-free. Avoid that while using a simple transformator. It costs about 2$ and really prevents your computer from getting unexpected noise/voltage/damage. Okay... if you still don`t know the use of my tiny switch, then you are: 1.) stupid 2.) lame 4.) stupid & lame Hmm...check it out... if you`ve got any problems, just contact me at L.O.R.E. BBS at any time ! Greetz, Dr. Fraud