how is a charge-only usb cable different?

[buenos]

how is a charge-only usb cable different than a usb data cable?
I have a usb charger, and when I connect a data cable between my Samsung galaxy s3 phone and the charger the battery charge current is about 20mA. When I connect a charge-only cable then the charge current goes up to 400mA.
Now I made an adapter to short the data pins on the phone side, but all it does is it makes the phone to display "Charging(AC)", but the current does not go up with the data cable.
Is the ID pin or the shield connected differently?
Pinouts.ru does not say anything about what exactly is needed to be connected to the ID pin and the shield.

 

[betwixt]

"charge only" cables do not need the two data wires, only the two power wires but they may have resistors at the powered end to program the USB source to set the correct current.

Brian.

 

[ZASto]

Samsung mains chargers have D+ and D- pins shorted together. That way the phone distinguishes between USB connection and charger connection.
I have Galaxy S Plus and Galaxy Core phones and both are reporting AC charging when connected to AC charger, or one that I made for my car with D+ and D- pins shorted.

So, it is not a special Charge only cable. It is an ordinary USB cable.

 

[buenos]

what is the required connection on the ID pin?

 

[ZASto]

Nothing, USB-A has only 4 pins not 5 like MicroUSB

 

[buenos]

the ID pin on the microusb side, that plugs into the phone.