Q: I have a question that might stump iLounge. Are there any accessories (alarm clock, speakers, chargers, etc.) that work with ALL of the following: A third-generation iPod, a second-generation iPod touch and an iPhone 3G?
A: If charging is not a consideration, any Works-with-iPhone certified accessories will generally work all the way back to the third-generation iPod for simply providing audio output. In fact, even earlier iPod speakers and related accessories will work with the iPhone, however you may find that some speakers do not filter out the interference from the cellular radio on the iPhone, requiring you to turn on Airplane Mode to listen to your music without this interference. Further, any accessories that are not Works-with-iPhone certified will display a pop-up notification to this effect as soon as you connect the accessory.
On the other hand, charging is another issue entirely, however, and it is very unlikely that you will find any accessory that can charge the original third-generation iPod and also charge the second-generation iPod touch, iPhone 3G/3GS or even the fourth-generation iPod nano. The problem is that all of the iPod models prior to the fourth-generation iPod would only charge using 12V power from the FireWire port, and were incapable of charging over USB. This is why the 3G iPod, which was the first iPod model to sync over USB, required a dual-connector cable so that you could both charge the device (via FireWire) and sync the device (via USB) simultaneously.
The fourth-generation iPod, introduced in 2004, was the first iPod model that could charge and sync over both FireWire and USB. This allowed it to continue to work with older 3G accessories that charged over the 12V FireWire power source, while also being able to charge from a computer’s 5V USB port.
From 2004 until 2008, all of the iPod models released by Apple, including the original iPhone, supported charging over either the 12V FireWire or the 5V USB connections, although the fifth-generation iPod in 2005 dropped syncing support for FireWire connections. In 2008, with the release of the iPhone 3G, iPod touch 2G and 4G iPod nano, Apple dropped the 12V FireWire charging support entirely, requiring these newer models to be charged only with USB capable accessories.
The 12V FireWire and 5V USB charging occurred on different pins in the iPod Dock Connector, and it would naturally be redundant and possibly even harmful to the iPod to provide charging power on both sets of pins simultaneously. As a result, there would not be any certified accessories that would provide charging power for both the older 12V FireWire-only 3G iPod and the newer 5V USB-only iPhone 3G or 2G iPod touch devices.
So basically, it comes down to the fact that any set of modern speakers that are designed to work with the iPhone will also work with the 3G iPod for audio playback purposes, but will not be able to supply power to charge the 3G iPod while you are listening to it.