Libra Libra special usb lead?

[Rizz]

Bought a Forma and a Libra for me and my wife, they both connected to my desktop and my wives Laptop without problem, but not my newer Laptop (what I needed them to work on). They would charge but not register with windows.

I finally found a little trick (you may have to reboot the kobo first), plug the micro side into the kobo normally, then put the other side into the computer SLOWLY, keep an eye on your kobo, as soon as you see the charge icon appear stop (USB should be about half way in), push and usb slowly another few mm in then the "connect to computer" option should appear, press OK. then push in a few mm more until you hear the windows chime. It should be working, don't touch the usb anymore or it may disconnect again.

[PeterT]

Out of curiosity what type of USB port is on your newer laptop? If it's a newer type (USB 3.x) try plugging an older USB 2 hub into that, and then plug your Kobo into the USB 2 hub.

[davidfor]

Originally Posted by Rizz

Bought a Forma and a Libra for me and my wife, they both connected to my desktop and my wives Laptop without problem, but not my newer Laptop (what I needed them to work on). They would charge but not register with windows.

I finally found a little trick (you may have to reboot the kobo first), plug the micro side into the kobo normally, then put the other side into the computer SLOWLY, keep an eye on your kobo, as soon as you see the charge icon appear stop (USB should be about half way in), push and usb slowly another few mm in then the "connect to computer" option should appear, press OK. then push in a few mm more until you hear the windows chime. It should be working, don't touch the usb anymore or it may disconnect again.

My reaction to that would be to return the laptop as having faulty USB ports. I have a similar issue with my laptop, but, it is about to celebrate it's fifth birthday and the USB ports are looser than when I got it. If I make sure the cable is pushed fully into the port on the laptop, there are problems. But, if I bump the cable, it is loose enough that the device might get disconnected.

[Rizz]

Originally Posted by PeterT

Out of curiosity what type of USB port is on your newer laptop? If it's a newer type (USB 3.x) try plugging an older USB 2 hub into that, and then plug your Kobo into the USB 2 hub.

My Laptop has a single USB 3.1 (and some type c's), I did read to try a USB hub, dug an old one out but was dead.

My reaction to that would be to return the laptop as having faulty USB ports

I can plug my phones into the USB port using the same cables without problems. but since I'm not the only person with KOBO connection problems, I though I'll sign up and share my finding if it helps anybody.

[Katsunami]

Originally Posted by davidfor

My reaction to that would be to return the laptop as having faulty USB ports.

It could be that this laptop (and the desktop and the other laptop) all work fine with a different cable. Cable/port combination is sometimes very finicky, on both ends of the lead.

[JSWolf]

Originally Posted by Katsunami

There are some cheap cables that are sold as "charing cables" or "data cables"; I have found that some of the "charging cables" actually only work for charging and not connecting to the computer, and some of the "data cables" only work for passing data and they don't charge.

I don't know the intricacies of USB, but if they have 4 leads inside, 2 for data and 2 for charging, you could presumably build a cheap charging or data-only cable by leaving out two of the leads.




Same. All of my cables and chargers are from either Anker, or RAVPower. Never had a problem with either.

I've only had one microUSB cable that was a charge only cable. I forget what it came with but it was clearly specified as a charge only cable. I've never had a data only cable.

Most of my third party (not included with the device or charger), came from Monoprice and I've had no problem with them.

[stumped]

i dont think a data only cable exists or would work if made ( would the PC sense it ? )

as for charge only - some gadgets only ever need charge not data e.g. vapes, portable power banks - those sorts of things are more likely to shop with charge only cables ( which may not be labelled as such?

[Quoth]

I think a data only cable can work. Power only cables do exist and are a good idea for unknown public sockets that might have malware, except then some gadgets that charge only take a lower current. The available current from a host is defined by existence or absence of two resistors on D- and D+ wires and if they go to +V or 0V. Higher current definitions are different for some makers, thus an iThing might only take full current from an Apple laptop or Apple compatible charger.
Also some chargers will confuse a Kobo ereader and make it "see" a PC host and it will offer to connect. Which is why you want a charge only cable before enabling the "USB Gadget mode" autoconnection without prompt in the configuration file. It should be possible to make a cable with the resistors compatible for your device on D- and D+ and then D+ and D- are not connected at "Host" end. Then you have to make sure and not use a USB power / charging socket with too low a current rating. PC host sockets are supposed to switch off if too much current is taken. You'd not want to assume a USB outlet built into a mains socket or that a USB charger does. Certainly most of the 12V Cigar socket adaptors just have a 5V IC regulator and the shut down or short current is whatever is designed into the IC. The D- and D+ lines may or may not have the resistors used by the gadget to sense what the maximum current is.

The host/charger NEVER sets charging current unless it's USB-C (which is so different it's not USB, it just can carry USB Data), it simply provides between 4.8 and 5.2V and the gadget decides what current to take. If more current is taken than the host socket/charger is designed for (like a short or a reversed V+ and 0V) it's supposed to turn off. This is a problem with USB-C as the maximum current is far higher than real USB and also it can do up to 5A and up to 20V. It ought to be 1A max at only 5V with shutdown if a short or reversed connection is detected in the absence of a command, but not all USB-C hosts/chargers implement it. A full power USB-C charger is much bulkier and much more expensive than a typical 1A 5V general purpose charger for USB.

USB has always struggled to keep up with the applications because originally it was only for joysticks, mouse, keyboard and small resolution cameras or small capacity memory (32 Mbyte = 0.032 G Byte was huge then). Stupidly it NEVER had peer to peer, so the extra pin was added on micro USB to tell the gadget to be a host instead of a slave, but then most gadgets can't charge in that state, though a few can with a special Y cable. A connector with up to 100W able to charge a laptop, or feed video and power to a display panel as well as do the USB serial data should have a new name. It's not USB which is purely a Host-Client serial data link with 5V only power. Even going more than 1A means lack of protection with faulty cables or gadgets. USB was 100mA, then 500mA. More than 1A was madness.

So anyway a power only cable is real, a power only cable that uses D+ and D- to indicate current that can be taken and only connects +V and OV at host/charger is real and a cable without +V and maybe even without 0V may work on some things.

Most cables sold as Charger cables are just ordinary USB cables. I've not found one that didn't connect D+ and D-, because then the gadget might only take 100mA or 500mA rather than 1A, 1.5A or 2A, with more than 1A or maybe 500mA needing a compatible charger / host as not everyone uses the same arrangement of resistors.

The so-called enumeration or smart charging on less than USB-C is nothing of the sort. There is no communication. Just none, one or two resistors on the D+ and D- lines for the gadget to measure voltage on. USB-C uses a separate communication channel, Vbus, thus it's not actually a USB connection at all. Simply using "USB" as marketing.


Apple does not comply with USB (see https://electronics.stackexchange.co...s-poweriq-work )
https://learn.adafruit.com/minty-boost/icharging

(called enumeration) where it says "hey, I'm about to drag 500mA out of the computer, just so you know" and the computer can say "go ahead" or "no can do" (this is called the power negotiation).

This is lie for children. The gadget simply measures the D- and D+ lines to deduce in SW or HW what current is available. There is no negotiation or signalling, except with USB-C.

This shows how silly it has got:
https://www.electronicdesign.com/tec...power-delivery
USB-C is so different to earlier USB standards it's only a marketing decision to call it USB.