Chatter

From ILB

Similar to a modern laptop, or more closely, a PDA/Palm Pilot, it seems to be possibly a form of techie nickname of the device. These chatters are very portable and are also used for off-line data storage similar to today's PDAs. Likely part communication device, locator, computer, or more. Kamal, numerous times, works on it as though it has a keyboard (though he types very slowly, appearing as though it's not a standard keyboard, but more of a PDA-style input method); Hiroyuki also tosses his away and destroys it at one point.

Chatter Protocol is the communication method used between chatters. Thus, you can monitor a person's chatter, or intercept CP packets and such. It also means you want to keep your chatter as secure as you can as long as you have it.

At one time, Aiden is reported as being 'offline', likely meaning his chatter is off (like turning off your cellphone) so Kamal couldn't directly intercept his chatter, but he had to spy through surrounding technology.