TEMPEST Technical problems! ! ! Dot matrix printer electromagnetic radiation!

[guijinjun]

Dear technical master, I am a Chinese student, I have a research topic is the information about the printer electromagnetic radiation intercepted and Restore, printers into dot matrix printer [epson LQ635K] and thermal printer.
Research is the main content of the printer via a portable device radiation information record keeping, the restore process in the preparation of the final reduction of the radiation out of the printer information content, content is radiated out of the printer you want to restore from the three Chinese characters of a text,
I consulted many Chinese scholars that they are unwilling to help me. Who can help me finish it, I will pay a reward.

MY E-MAIL:471545368@qq.com tthank you for everyone!

 

[HMS1021]

The only application for this technology is to capture data from a printer (keyboard, PIN pad, data lines, etc) remotely without being detected.

 

[E Kafeman]

Collect sum of EMI radiation level as a detector of how many pins in a printer head that was involved in a specific point of a paper is old and relative simple technology, not worth any research. Matemathical anlayze of recoverable information content have also been done 30 years ago, at least for the english language. With a bit more modern EMI collecting and processing technology can result be improved but most results in this area are classified.
An old dot matrix printer do nowadays seldom deliver information worth complicated analyzing. Install a backdoor at the victims mailserver is much simpler, have I heard. :roll:

 

[guijinjun]

I think you're absolutely right. Can you help me?

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The only application for this technology is to capture data from a printer (keyboard, PIN pad, data lines, etc) remotely without being detected.

I think you're absolutely right. Can you help me?

- - - Updated - - -

Collect sum of EMI radiation level as a detector of how many pins in a printer head that was involved in a specific point of a paper is old and relative simple technology, not worth any research. Matemathical anlayze of recoverable information content have also been done 30 years ago, at least for the english language. With a bit more modern EMI collecting and processing technology can result be improved but most results in this area are classified.
An old dot matrix printer do nowadays seldom deliver information worth complicated analyzing. Install a backdoor at the victims mailserver is much simpler, have I heard. :roll:

About the technical literature are few in China, so I do not know how to start, the printer and a host computer is not within the Internet, is just a play a computer connected to a printer, can you help me？

 

[E Kafeman]

1. Analyze how wide spectrum that emits from actual printer.
2. Build a direct converting receiver that can collect this spectrum.
3. Filter/demodulate/decode in software. Good understanding about what kind of modulation you actually is searching for is important.
Result looks maybe like Morse and do probably have a certain error rate due to RF noise. For translating to letters with good result, is knowledge of type of likely content and actual language construction of value. Search Google fro "frequency analysis".
Buy a book like this one: https://books.google.se/books?id=YgT74UPmOk4C&pg=PA18 and implement fitting algorithms/lexical in a software.
Details must you solve by your own.