How long can a USB C to C cable be?

USB C to C cable configurations span multiple versions.  As of this writing at the end of 2022, it spans USB 2 to USB 4.  But, rather than confusing you with different versions which could be meaningless to normal people, I'm going to break it up by speeds first, then version.

Here are the max lengths of cable assemblies, per the USB C spec (Table 3-1 of USB Type-C Cable and Connector Specification*)

Speed	Version	Max Length Meters	Max Length Inches
500 Mbps	USB 2	4	157
5 Gbps	USB 3 Gen 1	2	78
10 Gbps	USB 3 Gen 2	1	39
10 Gbps	USB 4 Gen 2	1	39
20 Gbps	USB 3 Gen 2x2	1	39
40 Gbps	USB 4 Gen 3	0.8	31

 *USB 3 Gen 2x2 is not included in the spec.  We added that for reference.

USB 1 - Now, you may be asking why we didn’t include USB 1 in our list above?  The reality is that it's normally only used in a very low speed device like a mouse or keyboard that already includes a captive cable, so we considered it irrelevant from inclusion.

Going longer lengths than USB spec – Longer lengths can be achieved, but longer lengths will result in a loss of signal integrity and power availability.  Signal quality drops pretty quickly beyond the lengths above, but you'll have to consider your application.  Studio photographers frequently use longer lengths without issue since there is normally not a constant flow of data and power can be obtained from the device or from a separate hub.

What happens if a cable is too long? - Too long of a length may work fine, or for a time.  However, heavy data usage applications, such as industrial / machine vision cameras, that use a constant stream of data will suffer the most.  Longer lengths end up causing data collisions that can cause failure minutes or hours into use.  These can be difficult problems to diagnose if you're not familiar with what you're doing.

Does a longer cable take longer to charge a phone or tablet?

I'm going to answer that question, and also answer a question you may not have thought of, such as charging time between thin vs thick cables.

Now, onto my essay.

Yes, longer cables that longer to charge, all things being equal.  The length of the cable matters, though not a great deal at shorter distances.

Which wire charges the fastest?  The shortest cables with the thickest internal power wires charge the fastest.  They have less resistance, and the faster the charging.  To help understand this, think about it in terms of a road.  The wider the road, the more cars that can get through faster.  But, the narrower the road, the fewer cars and more congestion (resistance), the fewer the traffic (charge) can get through.

If you’ve heard of ‘fast charge’, this normally means that power wires are of at least a thickness of 24 gauge.

Why not just use huge wires?  We could, but the problem that we face is that thicker wires tend to be less flexible, and with devices getting smaller and lighter, it can shift them around making it tough to hold, or tough to keep in a cradle.  For example, I have a Galaxy S7 phone with an aftermarket charging adapter.  When I set my phone next to my night stand, a thicker cable (even our standard cable) is tough to manage while I’m reading the news; the thicker wire makes charging bulky and cumbersome.  So, in this instance, an extra-thin wire is my preference, especially since I’m likely going to allow it to charge overnight.  Our ultra-thin wires (which use a super thin 30AWG) will normally charge my phone in about 4 hours when it’s at about 15% battery life left.  However, if I’ve forgotten to charge the phone overnight, in the morning I’ll opt for a thicker wire that would charge faster.  Our normal wires (which are a thicker 24AWG) will normally charge an almost dead phone in less than half that time.

Test Scenario: I purposefully ran my phone down to 10% to give you a real-life scenario of a charging scenario.  Now, one caveat, this only works with devices that are capable of fast charge.  I have 2 tablets, an Amazon Kindle Fire and a Galaxy Tab – neither of these are fast charge, so even on this same fast charge setup, they’re still slow.  Your device must be fast charge capable for this to apply!

For reference, the below chart is my Samsung Galaxy S7, testing 2 cable types: Regular (RR-AMCB-XXG) and Ultra-Thin (RR-AMCB-XXGX).  I also have a second chart that shows the cables along with a charging dock.  The charge time are the approximate charging times that are noted by my phone, about 10 seconds after charging has begun.

The results:

Aftermarket “Anker” charging adapter I bought on Amazon

10% Battery Life
Cable Length	Cable Type	Charge Time
1ft	Regular	1hr 47min
	Ultra-Thin	1hr 54min
4ft	Regular	1hrs 59min
	Ultra-Thin	3hrs 7min
8ft	Regular	2hrs 19min
	Ultra-Thin	4hrs 19min

Generic wireless charging dock that states “Fast Charge”

11% Battery Life
Cable Length	Cable Type	Charge Time
1ft	Regular	3hrs 7min
	Ultra-Thin	3hrs 7min
4ft	Regular	3hrs 7min
	Ultra-Thin	6hrs 14min
8ft	Regular	3hrs 12min
	Ultra-Thin	6hrs 14min

*Some setups are made up of 2 or our cables that are daisy chained together.  I did this as a test scenario in order to ensure I was testing exact lengths.

So, you can easily see, from the chart, how much the different variables correlate to charging times.

Hopefully this helps you make better decisions on cable buying.

One last note, cable ‘thickness’, does not necessarily reflect wire thickness.  We sometimes order different cables from places to see what our competition is doing.  We have noticed that some use a thicker ‘jacket’ to give a thicker appearance, but still use thinner wires inside.  So as they say, buyer beware!

Side Note: The longer length of the ultra-thin ended up being really handy if I wanted to set my tablet up in the bed and charge something without a cable bothering me.  For that, it worked like a champ.  Today is July 27, 2018; and we will likely now build a longer ultra-thin cable for charging just for that purpose.  If you have any ideas that you think might be interesting to see tested, let us know.  We thrive on customer feedback.

USB Superspeed and Machine Visions/Industrial Cameras

In our market, we have many customers who are having problems with cables that they've purchased elsewhere.  They have data integrity problems (ie, the cameras aren't as fast as they should be due to dropped frames), or during device testing they have ESD or EMI problems.

After so many years in this industry, we have come to learn a lot about the intricacies of building a proper USB cable - one that is not just to spec, but one that is properly made for a specific industrial application, like machine vision, which can require tighter specs than what the USB spec requires - especially if you need to go outside of the spec, such as needing an extension cable (which is not permissible in the spec) or if you have a high static environment and you need to drain the ESD (no fixes listed in the spec), nor using angled connectors (only a couple are even listed in the spec, and those are solely for USB 2).

Because there are so many things that we could discuss, I would like to welcome you to contact me directly for a specific question.  When I find some that are noteworthy enough, I'll publish the details here for the common benefit and the advancement of proper techniques within our industry.

To be frank, for an advanced level of usage of USB 3.0 / USB 3.1, the scope that we need to operate at is very high; unfortunately, many cables that we've tested, even cables that have been certified, are so loose within the spec (although they do appear to be within spec) that they cannot fit into an MV application.  They cause strange errors and differ from cable to cable.  It's unfortunate, but the reality.

So, as I get your questions, I'll publish more.  Contact me at our website, USBFireWire.com

USB Splitter Cables

USB Splitter Cables

There is a lot of misinformation out there about USB hubs and USB splitters in general.  I am going to try to help clear up the confusion.

Here are the two main questions I get
1.) How to hook up 2 computers to 1 printer with USB (as stated as the original question here).
As the previous poster said - you need a switchbox, not a hub (or also commonly referred to as a splitter).  There are 2 types of switches that you can use
   a.) Manual switch - with this, you have to manually switch the box in order to print from each computer.  It's cumbersome, but available.  Your computer will have to re-recognize the printer each time.  It's cheap, but available.  Just search for "USB manual switchbox" and you'll find tons of them for sale - they start at about $15/ea - shipped
   b.) Auto switch - a switch like this is highly recommended.  These switches will auto-sense a print job, switch it over to the computer that is printing.  I've used these several times and they generally work well.  The cheaper ones can be a little flaky - not sensing correctly and having to reset it, but the really expensive ones are really only necessary if you're doing this in a commercial/industrial setting; where it needs to work flawlessly.  There are differences between them, for sure.  For this item, simply search for "USB autoswitch" and you'll pull up a lot of results.  These start at around $18/shipped.

2.) The second question that I get is "do you have a USB splitter"... they don't want a hub, just a splitter.
First of all, in order to split USB, you have to use a hub.  It's a digital signal, which means that there is electronic data that is routed.. It's not like an analog system, like audio, or VGA, where a signal can flow to multiple devices.  For that, you need to use some type of hub.  The confusion is the references that are made.  A true USB splitter will split a single USB connection on a computer into multiple connections so that you can plug in multiple devices, like a keyboard and mouse, into a single port on your computer.  There are many out there, from Wal-mart to Best Buy, to Joe's Computer Shop down the street.
Here's a link to one that is offered at USBFireWire - it's a little higher end product (commercial quality). http://www.usbfirewire.com/parts/rr-usb2-splitter.html  It's only for this use - this won't work as a usb switchbox, and it won't work in the reverse (ie, in the above application).  It's solely meant for 2 devices, like a keyboard and mouse, into one port.

I hope this post is detailed and helpful.

**UPDATE and WARNING** I have also found a second type of USB splitter on the market.  It appears to be the same the original one designed by USBFireWire.com, but is instead wired direct.. however, only partially.  They claim that it can charge two devices, but only transfer data to one.  I thought, what the heck are they trying to do?  I found out that they have no 'hub' chip in the splitter, it's a simple straight wiring.  This can cause huge problems!  If your device negotiates a certain amount of power flow from one device, then output that to two devices, you could either be in for a slow charge (not a problem, just slow charging), but in a worst case scenario, your device could negotiate a higher charge rate (think fast-charge) and could overload your other device and blow your device if it were to receive more power than it can accept, or the cable you have plugged into the extension could burn the wiring if it's not made to carry that much power.  So, know what you're purchasing!

MHL Extensions, and MHL adapters

I recently had a few customers who were really frustrated.  They bought what they thought was an MHL extension for their S4 or Note 3, only to find out that it didn't work when they tried to connect it to either their SmartDock, or to their MHL adapter.  They had bought the Model: 4XMHLADAPTER called the "MHL Adapter Cable for Samsung". 

So, I decided to purchase one of these cables to try it out myself.  After all, it sure looked like the cable that we built.  What I found is that it looks similar, but it's not fully MHL 2.0.  The male connector is MHL 2.0, but the female is MHL 1.0 (aka, USB Micro-B).  No wonder it didn't work with the MHL 2.0 items.  In fact, I don't really know what you'd use this cable for - there's really no reason that I can think of to use this adapter.

Here are the female connectors from both.  Ours is on the right, which is why it's compatible with the newer Samsung phones and MHL items, like the dock and the MHL cable.

If you look closely at the picture above, you can see that the one on the left is flat at the bottom, that's the MHL 1.0 version.  The one on the right has a notch in it, that's the 11pin MHL 2.0 connector that works with the newer Samsung phones, such as the S3, S4, and Note 3 (and probably beyond as they continue to make new phones).  FYI, it's not just for Samsung devices, it's also relevant for those of you who use the Pioneer AppRadio - so take note!

Here's a link to our MHL 2.0 Extensions: http://www.usbfirewire.com/Parts/rr-mhl-ext-xxg.html

If you're wanting an MHL 1.0 Extension (think Galaxy S and S2): http://www.usbfirewire.com/Parts/rr-mcb-ext-xxg.html

USB 2.0 Micro-B - MHL - The difference in real life terms - with pictures!

I get so many questions from people asking why a regular Micro USB extension won't work on their new Samsung Galaxy S3, S4, Note 2, etc..  They have a case on their phone and it won't fit into the dock they have.  I've heard about 11 pin connectors, and 14 pin connectors, and they heard something from a friend or bought something from Hong Kong on eBay and are upset because it just doesn't work.

Well, hopefully this blog will help to answer most of the questions out there and take some of your frustrations and questions about it.

First, there is a USB 2.0 Micro-B Female (Receptacle) on most, if not all, Samsung Galaxy/Note phones.  However, look closely, there are differences.

Samsung Galaxy S2 - I personally have this phone as of today, October 2, 2013.  It has a pretty standard USB 2.0 Micro-B receptacle, and it's also MHL compatible, which means that a regular Micro-B Male will fit into it and work fine, but if I want MHL capability, I have to buy an MHL adapter that will work with it.  Think MHL 1.0  Here's one from Newegg: Product Link

Samsung Galaxy S3, S4, Note 2 - These all use a special USB 2.0 Micro-B / MHL connector - but if the last one is MHL 1.0, think of this one as MHL 2.0, since it has 11 pins in it.  The connector design is a bit different, which also means that the fit is different.

From the image below - you'll see two phones.  The top phone is a new Galaxy S4.  The bottom phone is a Galaxy S2.  The easiest way to tell the difference between the two ports is pointed out by the red arrow.  You will see the notch in the MHL 2.0, which you don't have in the MHL 1.0

While a Micro-B will plug into either one for charging, the MHL functionality is different.

MHL 1.0 could be extended with a standard USB 2.0 Micro-B, 5 wire connector, Here's one from USBFireWire.com: Product Link

MHL 2.0 requires a special 11pin connector.  The MHL 2.0 (left, below) inserts almost 2mm further than a standard Micro-B (right below) connector.  It also looks just a little different - you can see the ridge that fits into the notch that we noted in the receptacle above.

See the image below

 

In the end, the two are somewhat compatible, but definitely not fully.  To extend MHL 1.0, you can use a standard Micro-B 5 wire extension, that we linked to above.  To extend MHL 2.0, you need one of our MHL 2.0 extensions, which will arrive mid-October 2013.  Product Link to MHL Extensions

How to tell the difference between Micro, Mini, and regular HDMI connectors

Right Angle HDMI
Micro HDMI Extensions
HDMI Mini Left Angle Cables.

With HDMI haivng different connectors, how can you tell the difference between them?  That's the question that we began asking ourselves when we started working on our own designs for the HDMI products that we're developing.  

HDMI uses 3 main connectors:
A - Regular HDMI - Used on most computers, TV and DVD players
C - Mini HDMI - Used mainly on larger DSLR cameras and tablets.
D - MIcro HDMI - Used on smaller cameras and some smaller tablets.

See the image below to find out which port your device has

Now, we found the most confusing one to be the Micro HDMI port.  It's a bit deceptive because it's very close in size to the Micro USB 2.0 size.  If you don't have them side-by-side, and they're not labeled, it can be very easy for even a seasoned pro to get confused.

To help clear things up, I went to my local best buy to peruse the tablet section.  I found one tablet that had both of the connectors side by side, the Kindle.  Here's a picture of it so that you can see the two side by side.  It's obviously a large picture, so it's much easier to see than with the naked eye.

So, from this picture, you can see that the Micro USB is slightly wider and shorter, than the Micro HDMI.

Hopefully this will help to clear your confusion, and what port that you have... that is, until you only have a Micro USB 2 that also includes MHL functionality.  We'll talk about that in another post, though.  The difference and incompatibility of some cables with MHL, and the varieties of MHL connections is a whole story all in itself.

Good luck