Pappy's Cheese Box
by Pappy
Not much has been written about the Cheese Box over the years, and much of what has been written is most often way off track.
Descriptions of the Cheese Box range from "Turn your home phone into a payphone" - yeah, right - to making a "Call Diverter."
Wrong again - diverters have their place, but they are completely different. A Cheese Box is a remotely placed device (box) that will accept two separate incoming calls from two separate phone lines, and connect them together.
Simple idea, but not always a simple device.
The best description comes from the inventor of the Cheese Box himself, Mickey Callahan, a.k.a., "Cheesebox Callahan," who made bugging devices for the likes of Al Capone. There's even a book about him.
The idea is to have one line for the "bookie" and the other line for "bettors" to call in on. The bookie calls one number and sits and waits. Bettors call the other number, one after the other, and place their bets. The bookie never has to hang up, they just listen for the next caller.
Now, the cops are eventually going to get the betting number and trace it, but all they will find is the Cheese Box by itself at some remote apartment or such. When the Cheese Box is compromised, the bookie hangs up and is never located.
Technical descriptions vary from a couple of Zener diodes and capacitors to elaborate relay and voice coil designs, depending on what type of older central office switch the lines were connected to.
O.K., so what good is that now? Older electromechanical switches had specific electrical characteristics that allowed devices such as the Black Box to work. It was common for them to reverse line polarity at different stages of a call. You won't find that with today's digital central offices. But there is a way.
Enter Pappy's Cheese Box.
The concept of Pappy's Cheese Box is to use VoIP as the medium.
Old and new technologies combined. You'll need access to the net, of course, and two VoIP accounts - there are lots of free ones, FWD, etc. I recommend using different services for each line to stall any tracing.
You'll need a two FXS port ATA such as the Linksys PAP2T (O.K., that gave us the name Pappy), two standard silicon diodes (1N4004 or equiv.) and an audio isolation transformer (RadioShack 273-1374).
Set up two anonymous VoIP accounts on the PAP2T. I use Free World Dialup and Gizmo. Change the following settings:
Now for the wiring: Put a diode in series with one side of Line 1 coming out of the ATA, then connect that line to the white and black wires of the audio isolation transformer.
If the ATA shows that the line is off-hook - the first green LED on the PAP2T will flash - then reverse the polarity of the diode.
You want the line to be on-hook (not in use) in its idle state.
Connect Line 2, in series with the other diode, to the red and yellow wires of the audio isolation transformer, also checking for proper diode polarity.
The theory behind this Cheese Box is that the PAP2T provides a battery reversal when called by an outside party, just like the old days.
The diode causes a complete circuit with one side of the isolation transformer when a call is received and holds the line open. The same goes for the other side, so relays are not needed to answer a line.
The transformer makes a talk path between the two lines, so the callers can hear each other.
Ring current is cut off, so that it won't be fed back to the other line.
Now, how do you use this thing?
Hide your Cheese Box in a data room or anywhere connected to the Internet other than your own house.
Give the second VoIP line a PSTN number so that it can be called from anywhere. I use IPKall and it's free.
You can figure out all the ways to be anonymous over the web. Start from a free Wi-Fi hotspot and call the first line through FWD or whatever.
Sit and wait for callers to call your published IPKall number and talk with them just like you're on your own personal loop around.
Tracing a call to you will be just as difficult, if not more so, than tracing a call from Cheesebox Callahan.
1:1 Audio Transformer (273-1374) Specifications Faxback Doc. # 9888 Coil Turns Ratio:......................................................1:1 DC Resistance: Secondary:..............................................60 Ohms +/- 10% Impedance:....................................................600-900 Ohms Frequency Response:........................................300 Hz to 5 kHz Insulation Resistance:.....................More than 100 megohms at 250VDC