Yes, the serial interface is still widely used in industrial equipment. I keep an old laptop with serial and parallel ports to use for that sort of stuff.
I was once an applications engineer for the company that provided about
1/2 the RS-232/parallel port/floppy controller/keyboard controller. Some good geeky stories about that job.
No, that's not the way it works. If you plug the Nexus 7 (the original anyway) into a USB port that only supplies +5V and ground it will not charge at all. If you short the data pins together it charges at maximum current (shows up like an AC charger). If you plug it into the USB port of a computer it will charge at 500mA.
Nope. Without those cables the tablet would not charge at all. I had some 2.1A car chargers and wondered why they didn't work at all. Once I used a cable with shorted data pins it all worked fine.
What did happen is that with Android 4.2 there is no longer a need for the special cables. But I am running 4.1 (ICS) because there are apps that won't work on 4.2 (JB).
A charger with a USB socket doesn't send data back and forth. The Apple chargers (and aftermarket chargers for Apple devices) follow Apple's "standard" for telling the iOS device the available current by setting the voltage levels of the data pins. Plug the same Apple cable into the USB port of a computer and the computer communicates with the iDevice to set the charge rate at 500mA.
That's true, but all the aftermarket chargers just copy what Apple dows since it's not difficult.
No, the standard works on computers because the computer communicates with the Apple device and negotiates a charging rate.
The supplied charger has the data pins shorted. Aftermarket chargers do not.
However it should be pointed out that with the Android 4.2 (Jelly Bean) update this is no longer the case. I am running Android 4.1 (Ice Cream Sandwich) on my Nexus 7 because there are apps I use that won't work under Jelly Bean).
No.
My old Dell laptop with a serial port died and I haven't had time (code for lazy) to fix it so I'm using a USB to serial adapter with one of my newer old laptops to program routers, switches and phone systems. The Domino's Pizza stores once had dumb terminals and serial connections back to a server for order taking and I did a lot of serial networking back then. Along with the 1A2 phone systems the stores ran fairly well but the employees kept dropping the keyboards on to the floor and losing the buttons. Some of those kids were so stupid they swept the buttons up and threw them in the garbage. The old 1A2 phones were so robust you could beat a robber to death with one of them then use it to call the cops. I rebuilt a lot of those old systems and servers with the 8 port serial cards in the office computers and a dial-up modems to send info to the corporate office. I still have some of that stuff around and it still works. ^_^
TDD
If there is no apple software installed on the computer there is no data passed between the computer and the apple device with regard to charging rate, so the USB port on the computer provides it's standardized 5 volts. ( You are talking about the 5 pin micro/mini usb standard that has an ID pin (pin 4) which is either grounded or not grounded for host or slave ID . It is NOT the data pins that are shorted. Normal USB A and USB B is a 4 pin connector, + and - 5volts, and Data + and Data.
-..
The supplied charger has the charging cable hard wired to the charger and has a 5 pin mini or micro USB plug with the ID pin grounded to indicate it is a "host" device - making the Android device or iOS device the "slave" device. The "slave" device then knows it is attached to a device specific charger and sets itself accordingly.
Without the grounded id, it sees itself as the host, and sets itself accordingly. Using a generic USB charger or a PC USB A port with a normal USB a to Micro or mini usb cable, there is no grounded ID pin.
It is still all part of the (extended) usb standard.
Under USB 2 and 3 there is a battery charging specification which specifies how much current the ports must be able to supply - 1.5 amps per port and maximum 5 amps on USB2 BCS 1.2, and as high as 2 amps per port under 3.1
Of course that's the way it works. *I repeat myself*: Google says so and I just checked it out with a bunch of my old generic chargers on my own 2 Nexus 7s (original and current model) and they *do* charge.
Heck even my iPad and iPhones charge on generic chargers. Now that would be a switch if Apple stuff could use a generic charger and Google tablets went proprietary and couldn't... 8-O
As long as I use the correct size generic charger, both models charge at max.
Aha!!! Say that again. "no longer a need for the special cables". Thank you. Boy that took awhile to come out, huh... ;)
So I guess that instead of posting this misleading statement:
You really meant to post:
On *my own personal Nexus 7* I chose to remain with an obsolete version of the OS in order to run some old apps and for this reason
*I* can't use a generic charger on *my* Nexus 7.But for those who don't have a Nexus 7 and might be thinking of getting one, Google has long since updated all (2012 and 2013 models) to Android 4.3 and they will work just fine on a generic charger of the correct size... no cable hacking required.
*NOT* true. USB is a "standard" but fewer and fewer are following the standard for charging appliances. More and more are doing an "Apple" and rolling their own, using the same connector. Some will charge on a standard USB port, some won't.
The aftermarket can only copy Apple after Apple ships their stuff. Apple will change their "standard" without telling anyone. There are now manufacturers who supply charge controllers with programmable charging profiles to cover future Apple (and others') products.
Only within the USB standard. Few, if any, computers know about the Apple "enhancements" to USB. Again, Apple isn't alone, here.
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