Today we will discuss over the Pirating Cable TV or air pay TV scrambling. This is used widely in Many areas without cable, and all of the systems in use, use essentialy the same System, that of SSAVI scrambling.
Discussion of SSAVI scrambling:
SSAVI stands for suppressed sync, audio video Inversion. This method of encoding video transmissions was developed by the Zenith radio corporation, who manufactures the vast majority of legal Unscramblers used today with this method. Suffice to say, SSAVI is the anti Christ of cable pirates. The system involves several less sophisticated methods combined to produce a severely scrambled signal which is very difficult to decode without the proper hardware. (i.e., a real box.)
It is illustraed by the name: suppressed sync:
This is the method discussed in part 1 of this Series, only worse. The sync portion of the signal is not transmitted on an Audio subcarrier, but in lines 1-14 of the picture information which are not Seen on the screen. Hence, the box must be able to isolate the first 14 lines of video and extract the information from them.
The audio is transmitted on a subcarrier in a similar fashion as the sync pulses in part 1. If you will remember, the audio was normal in the suppressed sync method.
The video signal is randomly inverted at the scrambling stage, resulting in a Negative picture when the signal is inverted. (Yes, like a camera negative.) The indicator for
Wether the upcoming frame of video will be inverted is also sent in the first 14 lines of video, allowing the box to begin inverting the signal before you See it.
All of these little bits of evilness exist independently of each other. The Signal may have all, none, or any combination of these things. Because of this, the box must be very intelligent. Also, because the box is used so widely, it must have a tuner, allowing your local transmitter to select what Channel they are using by tuning the box before they give it to you. All this Makes for a real fun time when you go to unscramble your signal.
the suppressed sync signal is transved from the first few lines of video mitted normally in the first few lines of video, which, incidentally, are transmitted normally. The box ‘sees’ these 14 normal sync pulses, and calibrates it to reproduce these sync pulses for the rest of the frame of Video. It then inserts these pulses where they are needed in the signal to produce a normal picture. This recalibration every frame is necessary, though. Sync pulses occur over 500 times every second, and if the clock were Not constantly revamped, it could get out of sync (oh god) with itself. Audio: The audio is transmitted on a subcarrier deviated about 15 kHz.
All the box does to the audio is retransmitting the audio on the proper frequency. Video Inversion: the video signal is randomly inverted, but the mode (inverted vs. Normal) can only be switched between frames, not between fields, making the job of detection and reinversion slightly easier. The box looks at a portion of Line (2, I think) and based on the logic level at a certain point in this line of video, the box reroutes the signal through an operational amplifier’s Inverting input. As a result, a signal received inverted is now correct, and a Frame of video ‘seen’ as normal is not routed through the inverter, and sent Straight to the rf modulator, which retransmits the corrected signal to the TV Set, usually on channel 3.
Physical description of the zenith SSAVI decoder:
the box is approx. 11″ by 7″, And about 2.5″ tall, including rubber feet. It has a round vertical travel Pushbutton switch in the rear left top corner, and in a small metal label on the top center of the box is engraved
About 1.5″ by .75″. There are 3 female f connectors on the left rear, and a 3 Pin power connector on the bottom right rear. The case is brown, with a wood Grained strip running around the horizontal center. A rather formidable device.
Some intresting features of the SSAVI system:
(when used by the pay-tv companies, koff koff) because of the extreme to which the scrambling of the signal Is taken, the system provides more security against the casual basement cable Wizard than any of the other systems in use today, save those now being Implemented by various satellite transmitters. These are really mean: digital Video transcription, fluctuating transmission frequency, and other fun Stuff. But that is another file, coming later. In addition to the complexity of the scrambling, each box is given its own internal id number, allowing each box to be addressed by the transmitter and shut off in the event a customer does not pay his bill.
In addition, each box contains a firmware code which is constantly being compared to that transmitted by the station. Hence, a stolen Box woll not work in another city, where it cannot be turned off by the normal method due to the fact that some one may already be using a box containing the same security code.
There are several more codes stored in the box:
those which determine the services to which a subscriber is entitled. (Such as Optional sporting events, nite life, etc.) These codes are stored in a volItile memory powered by a rechargeable battery, to allow reprogramming from the Station. This also means that if the box is stolen and/or left unpowered for several days, the battery will run down and the authorization codes will be Lost.
Well, as usual, where there is security, there will be security breakers, and this is no exception.
Talk to these people about getting your own SSAVI box:
Video electronics 3083 forest glade dr. Windsor, Ontario n8r 1w6
Fone: 519 944 6443
According to them, the box also works with SSAVI cable systems. This is the Real thing, made by zenith. Why do you think you have to get it through Canada?
Channels these people guarantee the SSAVI box to work on: Ann Arbor 31, Baltimore 54, wash. D.c. 50, Chicago 66, Dallas 27, Minneapolis st Paul 23, san Jose 48, st. Louis 30, Tulsa 41, Boston 27.
Well, there you have it. They want $130 for the box, and with a $21/month fee it will pay for itself in 6 months. Have a good time.