Reply to post: Re: Plugs....

User couldn't open documents or turn on PC, still asked for reference as IT expert

Flocke Kroes Silver badge

Re: Plugs....

In the days before USB, devices were either Data Terminal Equipment or Data Communication Equipment. If by some miracle they had the same number of pins on the connector, they could in theory be jammed together to communicate. In real life, a simple straight through cable with connectors of different genders at each end was required. Sometimes someone would need to connect DTE to DTE. This requires a cable with the same gender on each end, but most of the connections crossed (eg Txd to Rxd). With great care and determination it was possible to buy null modem cables that did this.

Then came "gender changers" - the same gender on each end, but wired straight through. Take a standard serial cable, add a gender changer and you can physically connect two PCs, and get really frustrated because they cannot transfer data. There were cables sold by computer distributors with "Null Modem Cable" written on the label, but wired straight through.

At about that time, ethernet design was just as bad. All cables had the same gender on each end. Computer to switch/hub required a straight through cable. Computer to computer required a cross over cable and some hubs had a port wired like a computer for connection to another hub.

After years of this rubbish, it became obvious to everyone in the industry how to design network cables: same gender on each end - cross over. Different gender on each end straight through. So what does Intel do with USB? Return to the DTE/DCE crap so that devices would not be able to talk directly to each other without an (Intel) PC. And what a surprise: USB gender changers turn up - just as useless as they were in the days of RS232.

Want to connect two computers by USB? You needed a chip hidden in each connector that converts USB to RS232 and back, plus PPP to turn it into a network connection. The cable looks just like a USB-A to USB-A, and some distributors think it is clever to save money by missing the chips out.

Next time you are having difficulty remaining calm and patient in the face of an ID10T error, remember it took us 18 years to get from USB-1 to USB-C.

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