Hack 100 Networking on the Cheap: Set Up a Direct Cable Connection


You don't need a full-fledged network to connect two PCs using XP. Here's how to create a fast, cheap connection that's great for sharing files and other network needs.

If you are reading this book, which is (as you know) called Windows XP Hacks, then you probably get questions and pleas for help from your friends and family all the time (or you will, now that you've read the book!). You're the "computer guy" (women can be computer guys too, my female editor tells me) and you have the ability to "make it better." If that's a fair assessment of your situation, let's go through a scenario that happens to us hacker-types quite often.

It's 8:00 on a Sunday evening, and the phone rings. Your neighbor is panicking, because his computer is acting crazy and he just finished working on a huge PowerPoint presentation for work the next day. You grab your trusty laptop and your bag of computer parts and go next door.

You sit down at the computer and play with it a bit. Sure enough, it's got problems. The CD burner doesn't work, and the floppy drive is shredding disks. How's he going to transfer his file to his work machine? He doesn't have a dial-up account or Internet access, so you can't upload his file somewhere and download it to your computer?or perhaps it's just too big for his 28.8 bps modem to send.

Lucky for you (and for him), he's running Windows XP and so are you. Since you've read this book, you have exactly what you need on hand to save the day. You transfer his files to your laptop, burn a CD of the contents, and yet again save the day. He offers you money, but you refuse, because you'll keep him in mind the next time you need to move your piano.

12.7.1 Remember the Boy Scout Creed: "Be Prepared"

Before you can be the hero in this story, you need to have the proper tools. You might not have all the parts you need on hand, but you can get them with a quick trip to your computer store. There are three different cables you could use: a null serial cable, a parallel data cable, or a null Ethernet cable. All three cables are shown in Figure 12-8.

Figure 12-8. Null serial cable with DB-9 and DB-25 connectors (left), null Ethernet cable (right), and parallel data cable (back)

A null serial cable is the most universal cable; nearly every computer manufactured in the last 10 years has a serial port. The disadvantage is that serial transfer speeds are slower than parallel or Ethernet speed.

A null serial cable is not a serial modem cable; they look the same, but the connections are different. For this purpose, you want a cable that has female connectors on both ends. Serial cables can have two different connectors on the ends: DB-9 and DB-25. The DB-25 is an older connector that has 25 pins. If a computer has a DB-25 connector, it is probably too old to run Windows XP. I own a serial cable that has a DB-9 and a DB-25 connector on each end but I haven't used the DB-25 connectors for years. If you want to carry a serial cable, it is probably safe to buy one that only has DB-9 connectors.

If you have cable and some connectors lying around your office, you can make a null serial cable by connecting the same numbered pins on each connector, starting from the upper left, except for pins 2 and 3. Those pins are crossed so that pin 2 on one connector goes to pin 3 on the other and vice versa.

A parallel data cable allows for faster data transfers than a serial cable. A parallel data cable is not the same as a parallel printer cable! What you are looking for has a male DB-25 connector on each end. It is often called a LapLink cable or an FX cable. LapLink and FX were commercial products that performed this function in the past. Since Windows XP has the functionality built-in, all you need is the cable.

A null Ethernet cable is your best bet in terms of speed and ease of use. The advantages are that it works with all modern Windows operating systems and will be the fastest connection you can get. The disadvantages are that older computers may not have an Ethernet card or they may not have TCP/IP installed. You can purchase a null Ethernet card at most computer stores for a few dollars.

You can build a null Ethernet cable if you have a RJ45 crimper and RJ45 modular plugs by connecting the following pins with Cat-5 UTP cable: 1-3, 2-6, 3-1, and 6-2. The other pins are not necessary.

The null serial cable and the null Ethernet cable can be purchased for three or four dollars each from almost any computer store. The parallel data cable is a little more difficult to find, but it's still a good choice. No matter which of these you choose, you will be limited to connecting only two computers.

12.7.2 Cheap Networking with a Serial or Parallel Cable

Connect the computers using the serial or parallel cable. Make certain that you are connecting the same type of ports. Turn both computers on and log in so that both computers are waiting for you.

Decide which of the computers will be the host and which will be the guest. The host computer will be the one that supports the incoming connection. The guest will be the one accessing the remote computer.

On the host computer, open the Network Connections control panel. Click on the link labeled "Create a new connection." Click the Next button to get to the screen titled Network Connection Type. Choose the radio button labeled "Set up an advanced connection" and click Next. On the next screen, choose the radio button labeled "Connect directly to another computer" and click Next. When asked "Host or Guest," choose Host and press Next. You will be asked what device you wish to use to make the connection. If you are using a parallel cable, choose "Direct Parallel;" if you are using a null serial cable, choose the appropriate Communications Port (the one to which you connected your null serial cable?it should be labeled on your PC, but if not, check the documentation) and press Next. You will then be presented with the dialog box shown in Figure 12-9.

Figure 12-9. Host User Permissions screen

This dialog box asks you which users will have access to the host computer. If you are unsure about the security of the computer, you should choose an appropriate user. If you know the guest computer does not present a security risk, just choose the Guest account and press Next. The computer now has a network connection called Incoming Connections.

You need to know the network name of the host computer. If you do not know it, on the host computer right-click My Computer Properties Computer Name. The network name is the name next to the words "Full Computer Name."

Now it's time to configure the guest computer. Again, go to the Network Connections control panel applet and click the "Create a new connection" link. Select "Set up an advanced connection," click Next, choose "Connect directly to another computer," and click Next. This time, when given a choice of "Host or Guest," choose the Guest radio button and press the Next button. When asked for the connection name, type the network name of the host computer. If all goes well, you should see the dialog box shown in Figure 12-10. If you do, click the Finish button to close the dialog.

Figure 12-10. The New Connection Wizard

At this point, you have a physical and logical connection between the two computers. Activate the connection by double-clicking its icon on the desktop or in the Network Connections control panel of the guest computer. When the computers recognize each other, you will be asked for the username and password. If you provided guest access on the host computer, you do not need to enter anything; just click the Connect button. If the connection is made, Windows XP will pop up a notification on the taskbar, as shown in Figure 12-11.

Figure 12-11. New connection notification

At this point, you have a network connection. You can use your Network Neighborhood window to browse or search for the host computer. Shared folders will work the same as if you were on an Ethernet network. If your folders and printers do not have permission for the user on the host computer, they will not have the ability to share files or print.

Keep in mind that this method is a one-way connection. One computer is specifically the host and the other is the guest. Those roles cannot be reversed without creating another connection. If you would like to be able to access the computers without designating one as the host, you will need to use an Ethernet connection.

12.7.3 Cheap Networking with an Ethernet Cable

If you need to connect two computers and you want a fast connection, you need nothing more than the null Ethernet cable described earlier. Both computers need an Ethernet card with correct drivers and the TCP/IP protocol installed. An advantage of the Ethernet option is that it works on all versions of Windows, as well as other brands of computers.

If your computer does not have an Ethernet card, you can purchase one for $30 or so. For most home applications, a 10BaseT Ethernet card is sufficient, though a 10/100 card is not much more expensive and can send 10 times as much data. There are also cards called Gigabit Ethernet, but they are considerably more expensive and very few manufacturers include this type of equipment in their consumer-grade equipment. My favorite Ethernet card is the 3Com 3C905BTX. It's reasonably priced and every operating system knows how to deal with it. The DLink DFE530TX and the SMC 1244TX are also widely recognized and can be found for less than $25. Installing an Ethernet card with the manufacturer's instructions in hand is not difficult, but if you aren't comfortable working with the hardware inside your computer, you should let a technician do the job.

Connect the two computers using the null Ethernet cable. If the drivers are installed on both computers correctly, a green or orange light will appear near the point where you plugged in the cable on each computer. These link lights indicate that there is a physical connection present between the two computers and that the two Ethernet cards recognize each other. If you do not see the lights, it means that the drivers are not installed correctly, the cable is not wired correctly, or the card does not have a link light. The most likely cause is that the drivers are not installed, but I find that about 1 cable in 10 that I purchase is wired incorrectly.

Once you have a physical link established between the two computers, it's time to make the TCP/IP protocol work. Go to the Control Panel folder and open the Network Connections section. (Under Windows 98 and Windows Me, this control panel is called Network.) Search for your connection in its list and double-click it. Then, open the item named Internet Protocol (TCP/IP). (Under Windows 98 and Windows Me, every card and every protocol are listed in the same dialog.) Search for the one that says TCP/IP and has the name of your Ethernet card next to it.

There are many ways to configure a local area network, but the quickest and easiest way to connect two computers using a null Ethernet cable is to set the values, as listed in Table 12-2.

Table 12-2. Suggested TCP/IP setting for null Ethernet connection

Computer 1

Computer 2

IP Address

Subnet Mask


Preferred DNS Server

Leave blank

Leave blank

Alternate DNS Server

Leave blank

Leave blank

At this point, the two computers will act is if they were on a larger network with routers and other equipment. You will not be able to access the Internet, but you will be able to share files and printers. The same restrictions apply here that apply to the other cabling options; the usernames on one computer must have appropriate permissions to access files and printers on the other computer.

If you plan to keep your cheap network connected all the time, use the Ethernet option. Ethernet has the advantage of being the fastest of the three cabling methods shown in this hack, and it is widely accepted as the high-speed networking choice. If you choose to add another computer at a later date or get broadband Internet access, the Ethernet option will be the easiest to adapt to the new network configuration.

?Eric Cloninger