WD19TB

That's the response I was expecting but was hoping there was something I was missing.  Thank you for the quick response!

I was thinking I could get an extension cable for a WD19TBS that we're setting up.  But there's loads of these posts talking about the 40 Gbps is what's limiting the distance.

But if there's only 1 VGA monitor (connected through a VGA to DP adapter), the user has low expectations and is coming from a 7 year old PC, doing spreadsheets, there's no need for fast video.  and if the 40 Gbps relates to file transfer, they have a 100Mbps internet connection, so the dock is not the weak link in the chain to get files on the web.

is it an all or none situation with the extension cable?  Either will or won't work?  Not that it'll drop to a slower speed if cable is too long?

And slower charging - again, not an issue.  Laptop will stay in place in office all week. Then maybe weekend trip home.  So slow charging is not an issue.

Is 

@MikeRenna  The next step down with Thunderbolt would be 20 Gbps, but I don't know if the WD19TB will run at 20 Gbps.  I've never tried it.  But I also haven't seen any extension cables that expressly support Thunderbolt 3.  I see several USB-C extension cables that say they're compatible with Thunderbolt 3 ports, but that isn't the same as supporting actual Thunderbolt traffic.  As an example, this one mentions Thunderbolt 3, but in the details it says it supports USB 3.x Gen 2 (10 Gbps).

But if you're only trying to run a VGA display, then why not save some money and get the regular WD19S instead of the TBS?  That's a regular USB-C dock rather than a Thunderbolt dock, and as such it comes with a significantly longer cable.  And it is more than capable enough for running a single VGA display and even Gigabit Ethernet alongside USB 3.x.  Technically the WD19TBS can run in USB-C backward compatibility mode, so I suppose even if you got a USB-C, non-Thunderbolt extension cable, you might be able to get the TBS to run in that mode and it would still perform identically to the WD19S in that setup, but at that point you're paying more for a dock that's a worse fit for your needs, rather than saving money on a dock that's less capable overall but that comes with a longer cable that you want.

@jphughan  WOW!  Thanks for all that info!

I'm clearly a noob, so please bear with me!

1) Why'd I get the TBS? - 'cause my noob thinking is that it's 'better' / faster / more options.  And as you mention, I heard (haven't actually tested it) but figured it's better to standard on the WD19TBS since it is supposedly backwards compatible - the dock would be usable even on PCs without thunderbolt.

2) I said a single 'VGA monitor' -  but it's actually a monitor with a VGA cable / connector (the 15 pin blue connector).  the cable was connected to the laptop with the VGA to DP converter.  Not sure what resolution the user has it at, but VGA is 640 x 480?  It's much higher than that. 

I know on my PC, I am using a couple year old monitor with DVI (white connector) and VGA connectors.  The specs say it does 1080p  I am using the VGA connector because it's going into an older KVM that has VGA connectors.  Windows 10 says the resolution is 1920 x 1080.  So would you call this a VGA monitor?  Sorry if I misspoke.  And side note - would I get more choices / higher resolution options if I used the HDMI

With that info:

business use (excel, word, surfing, email), 1 (or maybe 2 at most) monitors that might connect with VGA or HDMI or DP or DVI (does it matter if with any of those, you choose 1920 x 1080 resolution?, gigabit network on the LAN, but going through firewall, likely not getting 1 GB out to the web. printing once in a while of just spreadsheets / word docs, etc.

Would you say the standard WD19 dock would work? 

What type of situations need thunderbolt?

Would you know how I can tell if it's in thunderbolt mode or not? How to put it in non-thunderbolt mode?  Or it's just built in - connect to a non thunderbolt laptop and it keeps working but in non-thunderbolt mode?

@MikeRenna  I forgot to address your last question.  When connecting the WD19TB(S) to a Thunderbolt-capable system, the dock running in Thunderbolt mode would normally be automatic, assuming you have the necessary Thunderbolt software installed on your system.  But on older systems, you have to "approve" Thunderbolt devices.  If you don't do that, then the peripheral will run in USB-C mode, or possibly won't run at all, because the initial wave of Thunderbolt devices did not support USB-C backward compatibility.

@MikeRenna Happy to help!

1. The TBS is indeed better, and its backward compatibility means that when using it with non-Thunderbolt systems, it has no drawbacks compared to using the regular WD19S....except that the cable is shorter, which seems to be a material consideration for you.

2. Yes, you're using a VGA display.  VGA can handle up to 1920x1200, although if it weren't for your KVM, I would say that if your display has any other input option, you should use that, because even if you're using a display with a native resolution that is achievable via VGA, the fact that VGA is an analog signal whereas everything else is digital means that it will look worse than any other option available.  Using another connector likely wouldn't allow you to use a higher resolution unless the display itself has a higher native resolution.  But if you've got a KVM, then unless you'd be willing to replace that, then you're stuck with VGA.  I will note however that DVI and HDMI are easily adaptable since up to 1920x1200 resolution, their signals are identical at an electrical level.  So for example if your display had a DVI input but you could only find HDMI-based KVMs, you'd be fine using DVI to HDMI adapters/cables as needed.

In terms of the use case you described, the WD19 or WD19S would likely work fine for your purposes.  It will be able to run USB 3.x and Gigabit Ethernet at full speed, and depending on the system model you're using (which unfortunately you didn't specify), you'd be able to run at least a single 2560x1440 display or dual 1920x1200 displays, or possibly a single 4K 60 Hz display or dual 2560x1440 displays.

The reason for a Thunderbolt dock would be if at least one of these were true:

• You wanted to use an actual Thunderbolt peripheral through a docking station, such as a high speed storage device or an external GPU.
• You wanted to run even higher-end display setups.  Again depending on the system you're using, the WD19TB(S) would be able to access up to 4x more video bandwidth than the regular WD19(S), allowing for setups such as dual 4K 60 Hz or triple 2560x1440.

But if neither of the above use cases would be relevant to you, then you'd sacrifice nothing by going with the WD19S, but you'd gain a longer cable and a bit of cash back.

@jphughan Thank you again!  You are too kind!  Not sure how you have time to help me and so many others.... I barely have the time to keep up with what I don't know : ) 

@MikeRenna  Thanks for the kind words!  I'm an IT professional and tech hobbyist, so that definitely helps me absorb and then share this sort of information, but I find the time because I see this as sort of my "pro bono" work to help do some good in the world, and doing good for others is important to me.  And it's thankful replies like yours that keep me motivated!

@MikeRenna  I think you're referring to docks that use "indirect display" technology called DisplayLink -- not to be confused with DisplayPort.  Dell's Dxxxx docks such as the D3100 and D6000 use that technology.  And yes it is a bit of a "cheat" mechanism and it does create some drawbacks that can be significant in some people's use cases.  I wrote about those in the post marked as the answer in this thread.  Dell's WD19 dock family models however do not use that technology; they tap into native GPU outputs.  But unless you're confident that the drawbacks of DisplayLink won't affect you AND you can get a dock like that for much less than a WD19(S), then I don't see a reason to recommend that solution.  Also note that the D6000 can only supply up to 65W of power to the attached system, whereas the WD19TB(S) can supply 130W and the WD19(S) can supply either 90W or 130W, depending on the power adapter it's using.  (The WD19TB(S) only comes with the higher wattage power adapter.)  So the difference in power output to the system may be another key factor for you depending on the requirements of your system, although I don't know because you still don't appear to have specified the exact system model you're using.

@jphughan 

: )

1 other question (for now!).

Was there something about 1 of the 2 types of docks - thunder or non-thunder - used a 'cheat' way to feed the video (at least in some situations)?  Some / all of the work was done by the laptop to convert / compress it and that could be buggy / not as good as just sending the video?  Any of that ring a bell with you?  Was that an older dock? Does that change your answer in any way?