max. VCDS USB cable length

Hi.

I'm currently planning the following:

There will be a USB socket in the garage, allowing you to connect a diagnostic cable directly to the car.
The house is attached to the garage, and directly next to the garage is a room with a computer.

I would therefore have a USB cable length of:
1.5 meters high wall.
2.5 across.
1.5 meters down.
0.5 through the wall.
2.0 for PC.

8 meters.

According to http://www.usb-infos.de/USB-FAQ-27000.html, I would then be in a gray area.
What do you think?


The goal of the entire initiative is to create a "senior-friendly" remote diagnostics system.
Plug it in, go online, make a call, and I'll take care of the rest .

m;

According to the specifications, purely passive USB cables should not be longer than 5 meters for physical reasons. Otherwise, the signal propagation time becomes too long, which is a very strict limitation. For whatever reason. It might still work, because many components are more tolerant than specified, but it's not guaranteed.
A simple active hub placed in between can extend the range by another 5 meters. For example, instead of using a standard connector on the garage wall, you can use a small hub (with a power supply, otherwise it won't work!), and then you can use a 5-meter cable to connect to the car. Head towards the PC, then go 0.5 meters through the wall. There are 2 meters to the PC, and then another 2.5 meters remain to position the hub in the garage in an optimal location.

Regards,
Christoph.

With a hub, it should be able to reach 8 meters.

Best regards, Rainer.

Hello Martin,

I've worked extensively with USB professionally (programming USB device firmware for mass production). Transferring 8MB at High-Speed (480 Mbit/s) is definitely not guaranteed. However, based on my assessment, VCDS might be able to function with Low-Speed (1.5 Mbit/s), which could potentially allow for the transfer of 8MB. It's likely, though, that it will be implemented as a Full-Speed device with a transfer rate of 12 Mbit/s. It's likely that the transmission is no longer working there.

Do yourself a favor and use a USB hub or repeater. There are plenty of devices that are bus-powered, meaning they can operate without their own power supply. Some models even allow for high-power USB devices (500mA), which isn't strictly USB compliant (a PC provides 500mA, and the hub/repeater would then need to have zero power consumption). Since the diagnostic interface probably doesn't use the full 500mA, and the PC usually provides more power anyway, I would prefer this solution to avoid using an external power supply.

USB-Spec compliant hubs/repeaters only allow low-power devices to draw up to 100mA of current. (I haven't yet checked how much current the VCDS actually reports to the laptop.) Perhaps that would even be enough.

Just use an active USB extension cable. At www.Reichelt.de, you can find a 5-meter long Bebel cable for €7, with the product number AK USBV2 AA-5.

"Additionally, there's one with a length of 10 meters (product number: DELOCK 82446). If the image is accurate, it wouldn't meet the USB specifications, as a repeater would need to be built into the cable every 5 meters, which isn't visible in the picture." Therefore, I would recommend using 1-2 of the 5-meter long cables (up to five links in a chain is not a problem according to the specifications).

PS: I just realized that you didn't include the cable length of the diagnostic interface itself in the specifications. That adds another 1.5 meters (?), and it definitely won't work passively anymore.

Regards,
Hendrik.

Or, completely different:

An old laptop is brought into the garage, which will handle the rest of the tasks via Wi-Fi.

He'll get features like automatic login, and then it will work.
Cables in the car.
Turn on the laptop.
Okay, I'm ready.

m;