Not all 30 pin iPad dock connectors are the same - seemingly

[Dave2002]

I have several different iPad/iPods with 30 pin connectors. Unfortunately Apple changed the connections several times, and now I'm finding it hard to charge up my old iPod Classic. I have a selection of wires, but mostly when I try to connect I get a message that the device is not charging. Sometimes it may be that the wire itself is faulty, but I think this isn't always the case. This happens with a few devices, not just the iPod, so I'm fairly sure it's the cables which are the issue.

It is becoming rather hit and miss trying to get some of the older devices charged up.

If I can get this sorted, I obviously need to label the cables as unlike ducks, the old rule "If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck." doesn't generalise well to iPad cables.

I have also had suspicions that the cables behave differently depending which charger they get connected to at the USB end.

[Frances_iom]

I have several different iPad/iPods with 30 pin connectors. Unfortunately Apple changed the connections several times.

welcome to the wonderful world of Apple lockin - they not only cheat on taxes.
One scheme adopted by Apple is add a different value resistor across two of the USB wires - the device measures this and will only activate charging if it matches - the technical reason is that the USB standard can only supply a limited current (insufficient for most charging) without first requiring an interchange of messages requesting higher current - most (all?) the el cheapo USB chargers don't honour this and just make 5V available at some maximum amperage (hence the fires produced by many such) - Apple claim that unchecked charging will damage the iPad etc (+ also prevent them making excessive profit but then most Apple devices are bought to demonstrate disposal wealth)

[Dave2002]

One scheme adopted by Apple is add a different value resistor across two of the USB wires - the device measures this and will only activate charging if it matches - the technical reason is that the USB standard can only supply a limited current (insufficient for most charging) without first requiring an interchange of messages requesting higher current - most (all?) the el cheapo USB chargers don't honour this and just make 5V available at some maximum amperage (hence the fires produced by many such) - Apple claim that unchecked charging will damage the iPad etc (+ also prevent them making excessive profit but then most Apple devices are bought to demonstrate disposal wealth)

I do have one cheapo charger which does seem to have suffered - the plastic has melted - but it was very cheap! I didn't know about the fires.

Until yesterday I also didn't know about some of the other features (variants) of the 30 pin connectors. Earlier versions had Firewire, but no video. Later ones took the Firewire off, but added in video. I think there may have been other variants over the years. This means that the wires are not always interchangeable.

https://en.wikipedia.org/wiki/Dock_connector

Re my Classic iPod, I could perhaps just "risk it" (probably not a huge risk) and use another charger, which could deliver sufficient, but not excessive, current.

[Dave2002]

Further to msg 3

http://apple.stackexchange.com/questions/100563/ipod-classic-80gb-wont-charge-from-usb-power-adapter

https://learn.adafruit.com/minty-boost/icharging

[Flay]

I lost my original ipod charger and lead so I use a lead from an older ipad. It will not charge from a transformer adaptor, but will do so from a computer USB port and also from a portable USB rechargeable battery. My preferred method is to attach the ipod to that battery while simultaneously charging it.

[Dave2002]

I'm not sure if the battery method works with my iPod Classic, but connecting to the MBP does work. The problem with connecting to a computer is that it runs the risk of iTunes trying to resync and generally mess around with what's on the devices.

I suspect that there are chargers and leads which will work with this particular iPod - just a question of finding them, or a combination which works.

I don't remember having to connect to a computer before to charge through a USB port.