0
\$\begingroup\$

TLDR: Can I solder a DVI-D Dual Link cable to a USB-C receptacle and will it work well?

According to the USB-C cable spec:

Figure 3-21 illustrates an example of USB Full-Featured Type-C cable cross-section, using micro-coaxial wires for TX/RX pairs. There are four groups of wires: USB D+/D− (typically unshielded twisted pairs (UTP)), TX/RX signal pairs (coaxial wires, twin-axial or shielded twisted pairs), sideband signal wires, and power and ground wires .

Also according to the spec, there are 4 pairs of TX/RX signal pairs and 1 pair of UTP wires.

Although I couldn't find the specifications for DVI-D, I could see by looking at the pinout and cutting into one such cable that there are 7 groups of wires wrapped in aluminum foil. Each group contains 3 wires, two twisted signal wires and one drain wire (does this mean shielded twisted pairs?). This, along with the information above, would make me assume that the two cables are compatible, ignoring wire gauge since I couldn't find any such info for DVI.

Assuming I don't plan on using power delivery, can I use a DVI-D cable to transmit USB-C 3.1 data?

Long story: I have been tasked with building a sort of a kiosk computer whose motherboard is physically separated from the peripherals. One requirement is that it must have a USB-C port, so I need to route a long (~2 meters) cable from the motherboard to the kiosk.

Ideally, I would use something like this USB C header cable from amazon.

Unfortunately, the panel where I have to mount it is so small that I can only fit a USB C female PCB connector soldered to a breakout board. I chose to use an Attend 217B-AG01, since this is what was readily available to me, which I soldered to a small breakout of my making.

The final problem I have is that the panel needs to be removable for maintenance purposes. As such, I can't just solder a cable to the breakout board and call it a day since that would mean I would have to either cut the cable to remove the panel, or to use a longer cable so that I can pull the panel off and have it hanging from the cable.

A better option would be to solder a small cable to the breakout board, which would have another connector on the other end of it. I could just use a simple USB C extension cable and chop off the male end to have it soldered to the breakout board, but I would like the free end to have a more secure connection, such a locking cable with a screw. I know there are USB-C cables with single screw locking plugs, but I just wasn't able to find a matching female receptacle cable. I suspect this is because the expectation is that the plug screws directly into the case/chassis of whatever you are connecting it to.

Alternatively, I could use molex or other kind of connectors with clips. The automotive industry is full of them. Problem is, even though the actual connectors and pins are cheap, the crimp tools I find are extortionately expensive.

This leads me to my question. There is one cable/plug which has enough wires/pins, is still somewhat common, can be found in both female and male variants and has locking screws: the DVI cable.

\$\endgroup\$
  • \$\begingroup\$ Why not use a hub to split it? \$\endgroup\$ – user3528438 Jul 9 at 7:19
  • \$\begingroup\$ They usually come with small length cables (think of dongles) and also don't have any locking mechanism. \$\endgroup\$ – user1969903 Jul 9 at 7:28
0
\$\begingroup\$

No, as USB and DVI don't use the same characteristic impedance for the cable.

| improve this answer | |
\$\endgroup\$
  • \$\begingroup\$ What would this mean in practical terms? Will data not be sent at all, will it be sent but at lower rates, would the cable heat up and represent a fire hazard, would it make a difference if I used the DVI cable just from the receptacle to the connector and a standard USB-C cable from that point on, in other words, will reducing the DVI length help? \$\endgroup\$ – user1969903 Jul 9 at 7:43
  • \$\begingroup\$ From what I gather from the specs, DVI is 100 ohm +/- 15%, and USB is 90 ohm +/- 5ohm, zo you might actually get lucky. It's a bit of a gamble and might depend a lot on the device you connect it to. \$\endgroup\$ – RJR Jul 9 at 8:38
  • \$\begingroup\$ It is pretty hard to say what actually happens in your case. It either does not work at all, works poorly, or it might work just fine. But it is the same thing why you don't use 300 ohm impedance microphone cable when you need to transmit DMX over 120 ohm impedance, or why you don't use 50 ohm coax to transmit video in a 75 ohm environment. The signals degrade due to reflections caused by impedance mismatch. \$\endgroup\$ – Justme Jul 9 at 8:42
  • \$\begingroup\$ @RJR thanks for the info. If this turns out to be the only issue, I guess I'll just try it out and see what happens. Just out of curiosity, where did you get this DVI spec from? I can't seem to find anything except wikipedia and cable specs from different manufacturers, but they contain DVI specific info such as display modes, pixels per clock cycle, etc. \$\endgroup\$ – user1969903 Jul 9 at 8:46
  • \$\begingroup\$ @Justme thanks for clarifying things. Correct me if I'm wrong but best case scenario is that it will simply be slower if there is signal degradation, since the signal is digital and checked for correctness. It won't hurt trying. \$\endgroup\$ – user1969903 Jul 9 at 8:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.