View Full Version : More Ethernet questions

Dee Gallo
07-04-2008, 9:37 AM
Okay, now I have decided to direct wire my ethernet to a hub so it can serve two lasers without plug-unplug to my computer. Also, I found out that when I put the IP address in the driver, my computer does not connect to the internet without switching the address back... Needless to say, this is a pain so I want to make a hub for the 3 connections (2 lasers and one computer) through an extension of my router. I hope I am describing this correctly. The router is in another room, so I can't go directly from the back of it, that would be too easy.

What I really need is the HUGE BRAINPOWER of SMC - I bought a NetGear 5-port ethernet switch, some Cat 5 cable and some connectors - now they want me to decide which I need to use: crossover or not? I have Bob Cole's wiring sequence, thanks Bob, for cross-over. IF I don't need that, does anyone have the sequence for a "regular" ethernet cable?

Also, if the "A" and "B" ends are different, which one comes frm the router, which one goes into the hub and then what do I use from the hub to the lasers?

Thanks in advance for anyone's help.

cheers, dee

Doug Griffith
07-04-2008, 2:19 PM
Hi Dee,
standard ethernet cables are straight through and are the same at each end. If you hold the clear ends next to each other, the colors of the wires within should be the same. ie. orange then red then blue then black...

When using a hub, the wire from the computer to the "in" port on the hub should be a cross-over. The wires from the hub to the attached machines should be standard. If you connect 2 hubs together, use a cross-over cable from the "out" of the first hub to the "in" of the second hub.

Good luck.

John Noell
07-04-2008, 3:40 PM
If it is something like the Netgear FS605 it automatically detects the connection needed and can use either a straight or a crossover cable. I am guessing that your Inet connection problem is because the router currently is using "DHCP" and wants to assign the IP addresses itself. If you turn that off and assign all devices (lasers and computers) static IP addresses (e.g., 192.168.0.xxx where all differ only on the xxx part) it should all work. (Order: wt-grn/grn/wt-orng/blu/wt-blu/orng/wt-brwn/brwn).

Dee Gallo
07-04-2008, 4:22 PM
Thanks Doug and John! You guys are lifesavers! Now I can put the ends on the cables.

I do have the Netgear FS605, so I DO still have to change the IP addresses so they are different at the last 3 digits, right? And, how do I turn OFF the "DHCP" thing on the router?

Sorry to be so helpless-sounding, but this is the first time I've ever dealt with this stuff. I sincerely appreciate your help!

cheers, dee

Doug Griffith
07-04-2008, 5:06 PM
Correct me if I'm wrong but it looks like the Netgear FS605 is an ethernet switch and not a DHCP router.

I'm a Mac user so can't really help you out. Check here for some info:


skip coyne
07-04-2008, 7:18 PM
a vs b both do the same thing you just want to be sure the two ends of each cable follow the same scheme

B is the one most commonly used but you can mix a and b on the same network without issues

like Doug pointed out you have a switch not a router so no IP's are being assigned by the Netgear unit

how are you terminating the ends ?

crimp or punch down ?

BTW rarely a need for a crossover as most modern devices sense whats needed (a crossover is simply terminating one end as A and the opposite end of the same cable as B )

Scott Perry
07-04-2008, 7:20 PM
Dee, if you PM your phone number I would be happy to help you.

Dee Gallo
07-04-2008, 8:17 PM
I just want everyone on this forum to know what a great guy Scott Perry is! He not only took the time to help me, but was patient enough to really make sure I understood what he was saying and what to do. He explained everything clearly and simply so that even I could understand... and that is saying something! I can't thank him enough!

We had a good productive and fun conversation and I thank you again, Scott!

And thanks to everyone at SMC - I'd be lost without this forum.

cheers, dee

Phil Sanders
07-04-2008, 9:07 PM
....I do have the Netgear FS605, so I DO still have to change the IP addresses so they are different at the last 3 digits, right? And, how do I turn OFF the "DHCP" thing on the router?

I hope you took Scott up and sent him your phone by PM. (I just saw you posted that all got taken care off. GREAT!)

But, for others who may read this thread:

You turn off the DHCP thing at your computer, and at the Laser Printers. This is mandatory. Unless your truly know what you are doing, don't mess with the setup of your router. Your router is doing something called Network Address Translation (NAT). Let your ISP configure your Ethernet to DSL router.

Dynamic Host Configuration Protocol (DHCP) only responds to broadcasted request for an identification number. If no device on the network asks for an IP address, then none are issued. Period.

Your router has two address: one for the real Internet, and an internal home network address. Don't worry about your real Internet address, as that is what your ISP is here for.

The entire Internet, and all the smart people who think of these things, a long time ago realized there were too few IP address around. So they set aside three bands of address for anyone to use inside a local network.

172.16.x.x (thru

These address are called non-routable IP address. You can Google that for way more than you will ever need to know. They are called because no ISP is permitted to send a data packet to such an address; you ISP is not permitted to 'route' such a packet thru the network. They are reserved for internal (ie home) networks. Your router lets you use these address, and then translate any packet for the Internet to your router's real IP address, and then sends the data packet on its way. Thus the Network Address Translation (NAT) thing. Return data packets are again reverse translated and sent on to your computer.
(Aside: consider how complex things get when inside your network you have many computers all sending and asking for replies from the internet, and your router needs to keep track of who gets what data package. Your DSL router is cheap. Guess where they saved money.)

For complex reasons we need not delve into, there are three parts critical to an IP address on the home side of an external Ethernet to DSL router:

IP address
Gateway (address of the gate, or router with NAT, to Real Internet)

Step #1 You need to find the static address of your Router, for it's home network side. (you don't need to know the IP address for the other side, the real Internet so don't look for it.)

One of the easiest ways is to let your computer get a DHCP address-
-on a Windows box, open a black screen command shell prompt

Start-Run -->CMD <Enter>

- Type in: ipconfig /all and then hit enter.
- Record the following: IP Address, Mask, and Gateway.
- You will use Mask, and Gateway. You should not use the IP address. You should choose other address. {Aside: If you have more than one Ethernet devices on your computer, things get complex quickly. Look for the one that looks like it is active.) You will use the first three number sets of the IP address, just change the last number set.

Aside: usually the mask used for home networks is set to or Either way use the same mask. What this means is a long 50 minute lecture on binary mathematics. Just let it go; the lecture is really boring.

Now in the setup of your Ethernet card is a check box for using DHCP, Un-check it. The last digit of the IP address you recored earlier, add 50 or some round number to the result is less than 254 and is not the same as the gateway number. Others just start off at 101 and go upwards.

Your computer's IP address usually will be the first three sets of numbers of the original DHCP address from above plus the last number set as you chose just above.
Example: Original DHCP numbers recorded:
IP Address:
Mask: (Caution!!! If you mask is you need expert help!)
You may choose:
IP address:
You enter this unique IP address (unique to YOUR home internal network) on your computer.

You must now also change the IP address of your other devices (IP Laser printer, Laser cutter, Laser engraver, what ever) to similar UNIQUE address (relative to your home network.)

As long as each Ethernet device has it's own unique IP address (relative to your home internal network) and each is set up with the same IP address same first three number sets, plus all are using the same mask and Gateway then all should be fine.

Be aware, you printers and engravers don't need to know the gateway address, and if given the choice, don't give it to them.

With a mask of you can have 253 devices on the network.

Notes on Crossover cables:
A crossover cable is used when you go directly from a computer to another Ethernet device such as a router or printer. You should not use a crossover cable with a hub, Ethernet switch. Please think of it this way: Your local large grocery store has one set of doors for in, another for exiting. Mostly everyone is happy going in and leaving by the correct door. However, sometimes on of the sets of doors is not working and all must use just one set of doors. Things just don't seem right with the world, and there is a bit of confusion at the door. Now we don't have a problem with one set of doors at the convenience store or the gas station, but at the Grocery store, it just don't seem right.

Under normal situations, all Ethernet connections should go to a hub or Ethernet switch. Like a spider web. And all connections come off the hub. But, like the gas station, sometimes you only get one door so you use a crossover cable to go directly from you computer to the DSL router or Cable Modem. Useful in troubleshooting a problem, however, when your ISP is trying to isolate the fault between your computer and their equipment; cuts out too many other potential problems on you home network.

Sorry for the long post.


P.S. Gosh I forgot about if your DSL router has wireless connection with DHCP. That could be a complex problem that will screw up everything I just wrote. Just keep in mind EACH home network device must have its own unique IP address, an address for the gate to the Internet, and a mask.

PPS: If anyone finds a error, please post it. I will try to correct my long post, but it is way too long and I know I missed something in my proof reading. Thanks.

Dee Gallo
07-04-2008, 9:40 PM
Yikes, Phil, it will take me a while to digest all of your information - thanks for taking the time to write it all out. I actually understood a lot of what you wrote! I have a good plan after talking with Scott, so I feel pretty confident. I won't be able to do the job until after July 12, so I'll have to post back my glorious success or horrible failure.:o

Well, I asked for the HUGE BRAINPOWER of SMC and you have not disappointed!

Thanks, dee

Mike Null
07-05-2008, 9:58 AM
I have one of my printers on my network and it does require its own gateway address in order to be used by my wired pcs and my wireless lap top.

Bob Cole
07-07-2008, 1:50 AM
You can have both DHCP and static configurations on your network. You will just have to verify what the DHCP range of addresses used by your gateway/router and assign any static device (printers/servers) to an address not in the DHCP range.

Good luck to you Dee.

I would also be willing to help if you need it.

Dee Gallo
07-12-2008, 8:43 PM
You can have both DHCP and static configurations on your network. You will just have to verify what the DHCP range of addresses used by your gateway/router and assign any static device (printers/servers) to an address not in the DHCP range.

Good luck to you Dee.

I would also be willing to help if you need it.

Thanks, Bob - I might have to take you up on that....

I managed to do the wiring inside the house thanks to Scott, and it tested fine with just my computer inside my studio. BUT - when I plug in to the NetGear FS605, I get no connection. All of the lights stay on all the time (power plus 5 ports) even if nothing is plugged in at all. I am using store-bought 3' patch cords so I can eliminate my poor wiring skills as a problem.

I have not even tried to set up the laser address since I am not getting any connection yet. So, I've reverted to USB for the time being.

If anyone has any info on what I should do next, I'd appreciate hearing your advice.

Thanks, dee

skip coyne
07-12-2008, 10:03 PM
when I plug in to the NetGear FS605, I get no connection. All of the lights stay on all the time (power plus 5 ports) even if nothing is plugged in at all.sounds like the switch is defective ,with nothing plugged in you should only have the power light on the link lights should only be on when the port links with a device at the other end

Dee Gallo
07-12-2008, 10:07 PM
Thanks Skip, I suspected that but they don't exactly give you clear instructions, they want you to register your first born online before you can get any tech support. I think I'll try to exchange it at RadioShack.

cheers, dee

Dee Gallo
07-13-2008, 1:03 PM
I exchanged the NetGear switch at RadioShack and eureka! The switch works, only the attached ports show lights, my computer can connect to the internet via the switch. :D BUT now, I got through part of the setup of one laser, changing the address on the laser itself... but the driver does not acknowledge the change automatically. I have typed in the address change in the printer window, but it won't change. I am also stuck at the "turn off DHCP" stage - where do I do that?

Sorry to be so clueless, I have zero experience with this stuff!

thanks to everyone, dee

Mike Null
07-13-2008, 1:29 PM

My memory is mush but I think windows has an automated thing on the control panel that'll walk you through this whole thing.

I first networked my pc's then my printer. Had a little help from the supplier on the printer but I think you've been given the gist of it.

Dee Gallo
07-13-2008, 1:48 PM
Thanks Mike, I'll look into that. I'm not really familiar with Windows, more of a Mac person. I'm always leery of changing settings but the Wizard might help me get through this.

cheers, dee

skip coyne
07-13-2008, 6:07 PM
sounds like its a laser issue rather than a windows issue . If your not using one why not pick up a router along with the switch that will assign IP through DHCP rather than your having to do it manually

if you can get radio shack to do it take back the switch and get a router with a built in 5 or 8 port switch or you could add a router to your existing setup.

Phil Sanders
07-14-2008, 6:45 AM

If I may jump in,

You turn off the DHCP thing at the device in question.

For a networked printer, that means either at the printer's control panel on the printer, or by software the printer's manufacture provides as a download from their web site. Sometimes, manual IP address don't change until a power reboot occurs.

Some newer printers have a small built in web page for manual configuration.

Print out a configuration page from your printer (at the printer it self.) This configuration page should provide you with the DHCP assigned IP address.
Now, you configure your (or any computer on your local network) to communicate with the printer at it's address. This computer must be in the same IP address range and mask; this may not be easy.
Open a web browser and put the IP address of the printer into the address box of your browser. (aside: Windows Vista and IE7, this may not function due to "security;" use FireFox)
The Printer's web page will appear. Turn off DHCP assign IP address you choose (don't forget the Mask and Gateway also.) Click the apply button.
You will loose the connection to the printer's web page as it implements the new IP address.
Return all other devices, such as the computer you are using to the normal IP range.
Print out a Printer configuration again for verification of IP address.
Aside: one printer I dealt with once needed a power reboot before manual IP address changes became effective.
Now try to connect your computer to the printer.

This looks longer than it really is. Only difficult if you let it be. A lot less difficult than doing a band saw blade replacement with adjustment of thrust bearings and guide blocks.

Hope This Helps


skip coyne
07-14-2008, 8:09 AM
easier to add a $39.00 router to assign IP through DHCP ;)

Dee Gallo
07-16-2008, 5:56 PM
Just another thank you to everyone who helped me get this !@$*^$ thing done!

I finally got the whole system working, 3 computers and 2 lasers online. After another setback of the router wanting to be reset every half hour, I was told to re-enable DHCP after all addresses were assigned, it solved all of the problems. Why? I have no idea. But it works!

For someone who never dealt with this before, it was certainly an experience... and I hope I never have to do it again! But I never would have gotten through it without SMC, THANK YOU!

cheers, dee

Scott Perry
07-16-2008, 7:29 PM
Dee, great to hear you got it going. Sorry I haven't been more help lately. We have had a big glass project going on and I didn't get to use the computer much.