JDM Tech Info

[vancinad]

@dimaryaz : Where were you able to find the technical information required to build this? Does Jepp publish an SDK?

[dimaryaz]

Hi! No, definitely no SDKs. I mostly figured it out by observing what JDM does, with occasional help from other users. Specifically:

• Downloading databases from Jeppesen: I intercepted http traffic between JDM and the jsum server and built a client based on that.
• Programming GNS 430 data cards: I recorded the USB traffic and figured out the USB protocol from that. Then one user shared datasheets for the chips inside of the data cards and answered the remaining questions.
• Transferring databases to USB drives / cards: I implemented a fake jsum server, which let me feed custom data to JDM and see what it did with it. I mostly guessed by comparing the input and the output. I had to do some reverse-engineering of the JDM binary to figure out some of the hashing algorithms.

[vancinad]

Lots of work! Very impressive. Thank you! Message ID: ***@***.***>