Hi, I'm planning to add multiplayer to my game via the USB port on the Ti84+CE and using <usbdrvce.h>. I'm trying to find the right cable to connect the two calculators. Initially I was just going to use a USB Mini-B to Mini-B connector. That's the end used on the cable to connect to the computer and would fit in both ends. Also, these are much easier to find to buy online in a variety of sizes and I really want a 10ft cable.

However, I have seen very many conflicting reports on if this would work. Some places say that what's really needed is a USB Mini-A to Mini-B cable. I'm a bit confused on why that would be necessary. Both types fit into the USB port and as far as I can tell they are electrically equivalent.

These say that a normal mini B - mini B would NOT work:
https://www.cemetech.net/forum/viewtopic.php?t=19239&start=0
https://www.amazon.com/dp/B0C1HPVXFS/ref=twister_B0CSWZ927N?_encoding=UTF8&th=1 A few Amazon reviews on this page say that it didn't work for them

These say that it WOULD work:
https://www.reddit.com/r/TI_Calculators/comments/16nqisn/about_ti_calculator_connect_port_and_cables/
https://superuser.com/a/828807/

One person in this thread says that it will work while another says it will not
https://www.cemetech.net/forum/viewtopic.php?t=14460&start=0

Can anyone who has ACTUALLY TRIED both of these cables for calc-to-calc communication please comment whether one or both of them work? Or if you have an authoritative source or reference.

USB Mini-A and Mini-B are not the same connector, and if you can buy a cable with Mini-B connectors on both ends it's not actually a USB cable because USB does not allow for a cable with the same connector on both ends (..unless they're both type-C, which we'll ignore).

Official USB-IF notes:


What the calculator has is a Mini-AB receptable, which can accept either mini-A or mini-B plugs:


When doing USB OTG, the device with the type-A plug is the USB host. When you're connecting two calculators you don't care which one is the host because they behave as if they're peers, so as long as you actually have a mini-A to mini-B cable it will work. A noncompliant cable with mini-B plugs on both ends will not work, because then neither device will become the protocol host.

Notably, USB mini cables may have a B plug but be wired as if it were an A plug. The difference is pin 4 (counting from the right in the diagrams in Tari's post). This pin is floating on a B plug but grounded on an A plug. It matters because USB is inherently asymmetrical, with one host and one peripheral (or more peripherals). The calcs will only be able to communicate if one side has it grounded and the other doesn't, but the shape of the plugs doesn't matter.

The same happens with micro USB, btw: A lot of phones in the micro USB era only had a micro B receptacle, but if you inserted an electronically-A cable, it would still allow you to use the phone as a host and e.g. connect keyboards or mice or hard drives. If you see a male-B to female-A OTG adapter, it is pretty much guaranteed the male-B end is electronically A (check the reviews, though). This is often done because the mini/micro A plugs are physically larger, so an OTG-capable receptacle that can only accept B plugs needs a B-shaped electronically-A plug to enable OTG functionality. An example of this is my 2017 phone or the TI-Nspire CX. My 2011 phone had a receptacle that could have micro-A plugs too, though.

No idea about the cables you've seen on amazon, though. Maybe they are actually following protocol and making one end A, maybe they aren't. It would certainly be nice if it was at least marked on the ends, so you knew which way you were plugging it in, if it mattered to you.

Also, notice regular-sized USB doesn't have 5 pins, it only has 4. The ID pin is missing, because full-size plugs and receptacles are completely incompatible anyway.

In this case, does literally nobody on Earth besides TI make a USB compliant mini B to mini A cable? I cannot find a single product to buy that isn't an Ebay listing of the cable that came with the calculator. Every product is advertised and displayed as Mini-B to Mini-B. Does anyone have a link to a non-TI cable that is Mini-A to Mini-B? Specifically I need one that is fairly long, and TI ones are very short.

I personally have seen a lot of cables that are Mini-B to Mini-B like shown, and they work fine with other devices. Are the device manufacturers adding some sort of auto-detection to this mistake so that they work? Or are all the cables wired so one end is actually A like fghsgh says?