| ^This.
I am an electronics engineer, and am looking into this from my perspective as designer of the equipment
In my view, i have the freedom to design multiple pieces of equipment, which are made to work with each other. For example, a computer and its power supply unit (particular example : Phone and its charging power supply unit)
I want to choose the connection based on my best engineering considerations, not on what some consortium somewhere dictates. After all, i do want the users to use the equipment, so i have absolutely no interest to leave users with equipment which they cannot connect....
Some companies took this as an opportunity to abuse the customer, but :
1. They will keep abusing their customers regardless of the type of connector, and have plenty of available ways to do it
2. This does not mean that there aren't legitimate considerations why i may want to use a connector which i think is best in my design, and abusing my customer is by far not what drives my design choices
But it does not end here. It only gets darker - from my side :
1. In order to put a USB device on the market, i have to have a unique vendor ID. Those IDs are issued by a single consortium, based on some terms i must agree to, and pay them royalties
I don't have to agree to any terms, or pay any royalties to anyone, to use a 5.5mm DC barrel jack, DB-9 RS232, RS422, RS485, 3.5mm phone jack analog audio, MIDI (1.x), many other common interfaces which exist all around us, and of course any interface i design myself for my device
2. We do like "stupid", not "smart" over-complicated technology, right ?
USB devices cannot be "stupid", even if it is only for power delivery. (They can, but they will have very limited capabilities)
An USB load can only draw 100mA at 5V. This means that even an USB cup warmer, which is essentially just a resistor in a nice case, must have some chips in it that communicate in the USB protocol, just to be able to negotiate 500mA from the host. (Most hosts will provide 1A no questions asked, and this is often abused even in commercial devices, but it is not allowed by the USB standard if i want to build my device by the book)
An USB power supply can be made "stupid", but only at 5V and IIRC 1A. Anything above that (up to 2.1A on USB type A connectors, or any of the PD power levels) must be negotiated
In contrast, i can run a common 5.5mm DC barrel jack at the absolute max voltage which is considered as "SELV" under IEC standards, at 3A or more on actually adequately sized contacts, delivering 150W+ of power, from a power supply which can be as stupid as 50/60Hz transformer with rectifier bridge
(It may be a dickhead move to provide 50V on a barrel jack of the same size that is commonly used for 12V in a lot of consumer devices, but you get the idea)
3. Communicating with USB requires device drivers
For the host to communicate with my device, it must have suitable device drivers. Here i have 2 options :
- My device presents itself to the host as a generic device of one of a few known USB classes, such as - HID (Human Interface Device - keyboard, mouse, not HPS lamps), Mass storage (flash drive, external drive), etc. My device then must fully implement the class i claim to comply with, and is limited to only functions that the standard includes for this class. It will work with the drivers existing on the host, regardless of the operating system it runs, so not require me to make and distribute any device drivers
- My device is whatever i want, and presents itself as Ash's custom USB device. For it to work, i must provide device drivers to be installed on the host
I may not have the desire to build and support complex USB device drivers, when all my device needs is pretty basic functionality. (It is becoming less of an issue nowadays, as there are chips available which implement virtually any class in an efficient and reliable way - which i can use in my circuit, but this have not always been the case in the past)
I may not have the desire to build and support device drivers for some operating systems. For example Windows, where the functionality of my device may break anytime due to any number of reasons which are out of my control, but still i get all the backlash and customer support expenses. And where, to get my drivers certified (so not show up concerning messages to the end users during install), may require me to sign things to Microsoft which i have no desire to sign
Now, if i already am forced to use the USB connector even when i dont want to, will i be forced to provide drivers for my forced-USB device too, in the name of "universal compatibility" ?
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