| SLE is a program written by PGM that is used to have a PC emulate a DirecTV smartcard, allowing people with the program and appropriate hardware to watch every DirecTV channel without paying a cent.
More specifically, SLE is a DOS-based program that acts as a firewall and emulator between the receiver and the smartcard.
Smartcard --- Computer w/SLE --- Receiver --- TV
This is done by reading data from your DirecTV receiver through a COM port, and then looking at the opcode. To help illustrate this, I break up the opcodes into three categories:
1. Inquisitive - These codes are basically the receiver asking the smartcard for some data. One common example is whenever a viewer changes the channel, the receiver makes sure that the viewer is allowed to watch the intended program. So the receiver will ask the smartcard Can he/she view this channel? Since the smartcard is most likely one that is not subscribed, SLE will act as an emulator and say Yes. Also, the receiver might ask the viewer's zip code (for sports blackouts) or time zone. In actuality, SLE is looking at an altercated file which represents the binary data of the smartcard to determine things like the zip code and time zone.
2. Decryption Requests - The DirecTV smartcard not only holds personal data, but an ASIC to decrypt the video signal. Since no one has yet figured out the decryption scheme, it can't be programmed into the SLE program. This is why you still need a card hooked up to the other COM port; SLE will simply pass this request along, look at the card's response, and then pass that response back to the receiver, which has no idea the data got examined.
3. Destructive - This is where the magic of emulation comes in. If DirecTV attempts to destroy a card, or write permanent data onto it, SLE will simply not do it. Instead, it might write data to a file that looks like the smartcard, but it never actually writes data to the card itself -- making it (theoretically) impervious to DirecTV's Electronic Counter Measures (ECMs).
All in all, SLE is a great little program which is written by one man (Pierre G. Martineau) who has decided to make it freeware. Anyone who steals DirecTV with his software is in his debt. :) | 
