Besides the significant hardware upgrades, the other selling point of the Apple iPhone 4S is Siri, the speech-enabled assistant that can help you schedule appointments, set reminders, read and compose SMS, and many other tasks. The technology is essentially a massive (considering how many iPhone 4S users are there in the U.S.) cloud-based speech recognition service reportedly provided by Nuance software.
Unfortunately Apple decided to make Siri only available on the iPhone 4S even though various resourceful hackers have proven that it can be run on the older 3GS and 4 models. Even the iPad 2 didn’t get Siri although its hardware is similar with the 4S.
Well, the folks at Applidium have cracked Siri’s protocol and published very informative technical details. Among them:
- Siri uses TCP port 443, over HTTPS (Secure HTTP)
- The request is a custom “ACE” method (as opposed to commonly used “GET”)
- Raw audio data is sent but compressed using Speex codec
- An iPhone 4S identifier is required with Siri