Why don't camera reviews cover the data connection to the PC?

On Sat, 27 Dec 2008 16:32:21 -0800, SMS wrote in :

Or you could simply ignore this nonsense.

On Sat, 27 Dec 2008 16:32:21 -0800, SMS put finger to keyboard and composed:

Don't you mean that "the Motorola *phone* uses a five pin mini-USB connector"?

connections

Ah, so the cable is not completely detachable, ie the charger end is hard wired? I got the impression from other posters that the cable was replaceable.

Yes, it appears so. It seems to me that, if the 5th pin were either grounded or floating as John Navas says, then the observations recorded by the people at pinouts.ru would not hold up. Obviously the ID pin cannot be grounded, as the USB OTG spec would then compel the phone to be a power giver, not a power receiver. So the ID pin must be floating, if it follows the USB standard. But if this pin were floating, then the voltage would not change when the charger is attached. Furthermore, there would be no need for a fifth conductor along the length of the cable. A DMM would confirm its absence, if JN were correct. Similarly, when testing for resistance between the 5th pin and ground, we would not expect to measure 200K ohms as others appear to have done.

- Franc Zabkar

OK. I admit. I'm confused. That's what I originally thought.

All I know for sure is that my entire box of mini-usb cables & wall chargers work on the Blackberry, but only the Motorola mini-usb cables and wall chargers work on the Motorola RAZR cellphone.

I think my Nuvi charger also works on the Blackberry but not on the Motorola RAZR (we can ask the GPS guys if they know more about the pinout).

So, I'm confused which is the 4-pin and which is the 5-pin standard.http://pinouts.ru/CellularPhones-A-N/razrv3_charger_pinout.shtml

Motorola: 5pin? Blackberry: 4pin? Nuvi: 4pin?

Which of these three is using the "correct" usb-standard pinout?

Right, because Motorola phones won't charge if you just connect +5V and GND from the USB port.

Actually, it's technically not true to say that Motorola doesn't follow the USB standard. USB was not designed as a way to charge portable devices, and Motorola is free to do whatever they want, but most devices with USB jacks for charging and/or data are able to charge with just +5V and GND being supplied.

Pat Cheney schrieb:

I think both of them are ok... Thats the nice things about standards. There are so many, you can choose whichever you want ;-)

And as far as I can see only the motorola phone is behaeving correctly, and all the other equipment is breaking the USB-Standard.

A USB port must be able to supply a current of up to 1A. But it is also true that You can connect several devices to one singe usb port (over a passive usb hub).

So a device has to draw at most 100mA (or 150mA) at the beginning of a connection. It has than to request more power from the host, which is keeping a list of connected devices and power consumption. Only if the port would not get overloaded, the host (in most cases a PC or laptop) will acknowledge the request. Otherwise the request is declined and the device is not allowed to draw more than the 100mA.

So A device that just draws full current without communicating with the host is breaking the rules.

For USB-Loaders there is an exception. The specification says that a simple loader should short the two data lines. Than the device is allowed to draw full current (depending on specification 1A, 1.5A or 1.8A).

So it seems the motorola device is behaeving correctly, while the other devices do it wrong. Attaching more than one such device which draws too much current to a USB Port might damage your Mainboard.

That's also the reason why these dual connectors which are sometimes used with external hard drives are out of specification (and useless in many cases anyway).

kruemi

Franc Zabkar schrieb:

kruemi

no, it's 500 ma per port.

And does that explain why you need 5 wires??

My reading skills must be impaired...

On Sun, 28 Dec 2008 09:46:47 +0100, Marco Tedaldi wrote in :

...

True. But off topic. Usenet is reserved for uninformed speculation and ranting, not facts. Please be more careful in the future.

On Sun, 28 Dec 2008 15:45:07 +0100, Sjouke Burry wrote in :

The 5th connection is device ID. See the USB specs.

On Sun, 28 Dec 2008 09:46:47 +0100, Marco Tedaldi put finger to keyboard and composed:

"A unit load is defined as 100mA in USB 2.0, and was raised to 150mA in USB 3.0. A maximum of 5 unit loads can be drawn from a port in USB

I couldn't find anything in the abovementioned Wikipedia article that discussed the 5th ID pin in relation to battery charging. AFAICS, this pin should be floating at the phone end, not terminated with a resistor to ground. Does the "Battery Charging Specification" redefine the function of this pin, or is Motorola's implementation non-standard?

- Franc Zabkar

On Mon, 29 Dec 2008 09:22:28 +1100, Franc Zabkar put finger to keyboard and composed:

This is the "Battery Charging Specification":

Fig 3-2 on page 13 shows a Dedicated Charger. The D+ and D- pins are connected via a resistor, Rdchgr_dat, which has a maximum value of 200 ohms.

The ID pin is left floating at both ends.

Section 3.10 on page 16 defines a "Resistive Detection Mechanism" whereby a portable device can differentiate between a dedicated charger and a hub or host charger by looking for pullup and pull-down resistors on D+ and D-.

In all cases the ID pin is floating.

- Franc Zabkar

On Sun, 28 Dec 2008 08:18:55 -0800, John Navas put finger to keyboard and composed:

Here are the facts:

USB "Battery Charging Specification":

A USB charger does not require any smart electronics, only a shorting wire (R < 200 ohms) between the D+ and D- pins. The 5th ID pin must remain unconnected.

This means that one really only needs 4 wires, so any implementation that uses a 4-pin connector would be compliant from an electrical point of view.

If we assume that a Blackberry charger is wired as per the above standard, then it should be able charge any compliant phone, camera, etc. However, it won't charge a Motorola phone because the latter expects to see a particular non-standard voltage on the ID pin.

OTOH, a non-standard Motorola charger which places 1 volt on the ID pin will not upset a compliant USB device (eg a Blackberry ?) because such a device expects this pin to be either grounded or not grounded. The device doesn't care whether the "not grounded" state is at 1V or

- Franc Zabkar

On Tue, 30 Dec 2008 06:08:57 +1100, Franc Zabkar wrote in :

Sorry, but that's your leap of faith, not what the spec says.

It's standard, and not a voltage.

Those are your contentions, not what the spec says.

On Mon, 29 Dec 2008 11:41:18 -0800, John Navas put finger to keyboard and composed:

Please explain, with references to the actual text.

The people at pinouts.ru have *measured* it. What have *you* done?

What *does* the spec say?

- Franc Zabkar

On Tue, 30 Dec 2008 07:47:27 +1100, Franc Zabkar wrote in :

No thanks, Franc, I've long since learned that arguing with you is a total waste of time.

On Mon, 29 Dec 2008 12:54:22 -0800, John Navas put finger to keyboard and composed:

Ah, it's the same old John Navas. When you having nothing to say, say it as convincingly as possible. If you say it often enough, at least

Unlike you, John, I don't promote myself as the fount of all knowledge. I accept that I am ignorant and fallible. And unlike you, I would never dream of trying to pass myself of as a consultant. As a consultant I could not afford to be seen to be wrong, as this would damage my commercial standing.

- Franc Zabkar

On Tue, 30 Dec 2008 08:21:49 +1100, Franc Zabkar wrote in :

And the same old Franc, ranting the same old childish goading.

Such is life.

On Mon, 29 Dec 2008 13:50:03 -0800, John Navas put finger to keyboard and composed:

I see no evidence that you're anything other than a deskbound specification junkie suffering from delusions of grandeur.

Here at sci.electronics.repair there are real technicians who understand which end of a soldering iron is hot. We also understand integrated circuits, ie those square and rectangular plastic thingies with lots of shiny pins.

If you can refute the work of the people at pinouts.ru, people who presumably are technicians themselves, then here is your golden opportunity to do so. What resistance or voltage do *you* measure on the ID pin of a Motorola RAZR charger?

- Franc Zabkar