Help for Direct Cable Connection

New Feature: I have created a resource that you can download to your hard disk to assist with the installation and configuration of direct cable connection. It uses screenshots to try to explain the process. You may download the 1.29 megabyte file here. Once downloaded, expand all files to a directory and open the file with "Start Here" in its name.

The Direct Cable Connection program creates a network connection over your serial or parallel port. Under normal network circumstances, a network interface card, such as an ethernet card or modem is used. For DCC, your serial port or parallel port is treated as your network interface hardware. We are making a network with hardware that wasn't originally designed for networking purposes, so it can be a little more difficult to get going.

To begin with, let's look at a model for how Windows Networking works.

                Applications (DCC in this case)
                
                _____________|________________
               |                              |
     Client for MS Networks         File and Print Sharing 
               |______________________________|
                             |
                          NetBIOS
                             |
                 ____________________________
                |            |               |  
             TCP/IP         IPX           NetBEUI
                |____________|_______________|
                      |                 |
                   Network        Dial-up Adapter (PPP)
                     Card               |
                      |              __________
                     LAN            |          | 
                                  Serial     Parallel (if DCC)
                                ____|____
                               |         |
                             Modem   Null-Modem
                              /           \ 
                         Phone Line     Null-Modem Serial Cable

Consider that when you are on an ethernet network, your computer is making a circuit down the left side of the diagram. If you want to do a direct cable connection, you are going to make a connection down the right side of the connection. You have to be sure to install the components for each layer. I will start at the top layer and work my way down.

Layer One

First you need to install the Direct Cable Connection program. To do this, go to Control Panel, then to Add/Remove Programs. From this window, select the Windows Setup tab. Select Communications and click on the Details button. Select the check box for Direct Cable Connection. Selecting this will automatically select Dial-Up Networking if it is not already installed. This should complete the top layer. (103K)

Layer Two

For layer number two, both components that you see in the diagram above will need to be installed. Client for Microsoft Networks will be our network client. File and printer sharing for Micorsoft Networks will be how our host computer shares network resources for the client to connect to.

To install Client for Microsoft Networks, proceed to your Network Neighborhood. This icon should be found on the desktop. If so, right click on it, and select properties. (A double left click tries to browse the network.) If there is no icon on the desktop, the icon can be found in the Control Panel. From the Control Panel, you must double click the icon. From the Network Neighborhood window, click on the Add... button. Next, select Client, and click Add... From the following window, select Microsoft on the left side, and Client for Micorsoft Networks on the right side. Click OK. The files will copy from your Windows 95 source disk. If you are prompted to restart your computer at this point, click NO because we will be adding some other components that also require a restart.

To add File and printer sharing for Microsoft Networks, the steps are very similar except you will add a service. This is listed also listed under Microsoft. Do not restart yet. After this service is installed, it must be configured. To do so, click on the "File and Print Sharing..." button from the Network Neighborhood window. Enable sharing for files in the check box. If you wish to share your printer also, enable the box for that. Other than the need to setup sharing, which I will address later, this should complete layer number two. (18K).

(49K) Picture of the Network Neighborhood window.

* You do not have to setup the NetBIOS layer. This is there for explanatory purposes. (I won't count that as a layer)

Layer Three

Layer number three consists of your desired protocol. You may use any of the three I have listed in this diagram. I don't know how to use protocols other than these. For most people, it is easiest to use NetBEUI or IPX/SPX protocol.

• Setting up IPX/SPX-compatible Protocol
  
  From the Network Neighborhood window, click on the Add button. Select Protocol, then click the Add button. Under the subset of Microsoft, select IPX/SPX-compatible Protocol, then click OK.
• Setting up NetBEUI
  
  From the Network Neighborhood window, click on the Add button. Select Protocol, then click the Add button. Under the subset of Microsoft, select NetBEUI, then click OK.
• Setting up TCP/IP
  
  From the Network Neighborhood window, click on the Add button. Select Protocol, then click the Add button. Under the subset of Microsoft, select TCP/IP, then click OK. TCP/IP requires some additional configuration before it will work with DCC. You will need to assign an IP address to your Dial-Up Adapter. Note that Dial-Up Adapter is not equal to your modem. Assigning a static IP address to your DUA does not affect the IP address of your modem when it dials in, and therefore should not affect internet access. I went into more detail about using TCP/IP on the following page: DCC with TCP/IP

Following the installation of your protocol, you should define a name and workgroup for your machines. The computer names must be unique on a network, but the workgroups can be the same. (The workgroups should be the same for simplicity.)

To define the computer name, select the Identification tab of the Network Neighborhood window. In the Computer Name field, enter in a unique value. Numeric and alpha characters are permitted. I would suggest making it a simple name like Bob and Rob. For DCC puproses it is simpler to make the workgroups the same. If you are in an office where this shouldn't be changed, that will be ok, it mainly affects browse lists. This should complete the third layer.

Layer Four

Layer four consists the Dial-Up Adapter. To install this, go the Network Neighborhood window. From there, click on the Add button, and select Adapter, and click Add. On the manufacturer side, select Microsoft; on the right side, select Dial-Up Adapter. Click OK.

Select the properties for the Dial-Up Adapter from within the Network Neighborhood window. Select the Bindings tab. Check to see that your selected protocol is bound to the adapter. Similarly, each protocol should be bound to Client for MS Networks, and File and Printer Sharing. For example, if you are using TCP/IP, you should go to the Network Neighborhood window, and select TCP/IP -> Dial-Up Adapter, then click Properites. Under the Bindings Tab, both services should be selected in the check boxes. This should complete layer four.

Layer five

This layer and those below it are the ones that I think can give the most difficulties.

• Parallel

  I don't expect the parallel port to give much trouble. Chances are, the parallel port is already installed properly in your system and in Windows. If your parallel port is not present, make sure it is enabled in your BIOS It should also be installed in Windows. To install the port, go to the Add New Hardware icon in the Control Panel and follow the steps.

  There are a few different types of parallel port settings. Normal, EPP, and ECP. As far as I have been able to tell, it does not matter which setting you use for direct cable connection, although ECP Enhanced Capabilities Port is supposed to be the fastest mode. I have successfully connected two PC's while their ports were in different modes from the other, but I would recommend setting them both the same in order to remove the possibility of trouble. This setting is changed from the system BIOS. As far as I know, the cables I used for parallel connecting were plain and simple parallel cables. Parallel connecting does not require a modification to the cable.

• Serial

  Most older computers used serial mice, and therefore their serial ports were ready to go from the factory. However, with more PS/2 and Bus style mice, some serial ports are not setup and enabled. I will write from the perspective of having a mouse on com1, and a modem on com2. (That is actually how my system is setup) If you do not have a serial mouse, then the mouse comments won't apply, however, the modem information will. (One exception may be WinModems, since they don't seem to use the traditional com port. I've never messed with one though.)

  Your motherboard (provided it is a within two or three years new) probably has an onboard I/O controller. Among other things, it manages your serial ports. Your motherboard has an oboard serial port one, and an onboard serial port two. Externally, we have communication ports, which use both the resources that these ports provide as well as the physical datapath of wires that they provide. In a serial direct cable connection, you are using both resources.

  A serial connection on com1 differs from a modem that is set to use com1 in that your modem talks to the computer over a bus and your DCC talks over that onboard port. They are similar in that a device on com1 uses IRQ 4, and Memory Range 03F8. (It uses the range from 03F8-03FF but we can truncate it to just 03F8.)

  What we have with the serial ports and the com ports is 
  an arrangement like this: 
   _________________________          _________________________ 
   \Onboard Serial Port One/          \Onboard Serial Port Two/
                        
          /       \                          /        \
         /         \                        /          \
        /           \                      /            \
      Com1         Com3                  Com2          Com4
  

  Since com1 and com3 use some of the same resources, (they use the same IRQ) the two com ports cannot be in use at the same time. For example, you could not use your mouse on com1 while your modem was in use on com3. Moving the modem to com2, would be permissible, however.

  In my case, the only com port I can use for DCC is com4. Com1 or 3 would conflict with my mouse. Com2 would conflict with my modem even if the modem was not in use. In that case, the IRQ would not be in conflict, but the memory range would. I can connect on com4 as long as nothing is using the modem. This image gives a graphical representation of the resources.

Installing the serial port

Before you can do anything with the serial port in windows, you must turn it on. Go to your system BIOS at the beginning of the bootup process, and find the appropriate screen. You should find settings for your serial ports one and two. Some BIOS are confusing because they allow for the first serial port to be 1, 2, or 3. I won't get into this one... Generally, they are Com1/Com3 On or Off. If your serial port is disabled in your bios, you will never get anywhere in DCC or Windows, so make sure it is enabled. Save the changes and reboot. Of course, if it is already enabled, you don't have to do this.

When you return to Windows, you will probably have to manually install the port. I've not seen it autodetect a serial port. Go to the Add New Hardware screen, and select Ports (Com & LPT). Select Standard Port types, and Communications Port. If you are going to use Com4, you may have to do this more than once.

At this point, I am going to refer you to my page about setting up null-modem. Otherwise, it will be redundant to say it all here. Null-Modem Page

Layer Six

For my purposes, this will be the physical piece of hardware that links the computers, the parallel or serial cable.
As I mentioned before, there shouldn't be much trouble in getting the correct parallel cable. Parallel Cable Pinouts

For serial connections, your cable must be a null-modem cable. This means that some of the pins are switched. Those two would be the send data and recieve data lines. An incorrect cable will cause the connection to fail. Generally, you can get a serial cable that is plain, and then put a null-modem adapter on it. Make sure you get the adapter and not a gender changer, which often looks the same. For details about null-modem cables, visit Serial Port Pinouts.

In the next dialogue box, you specify a share name. You can keep things simple. Share drive C: as C, and folder Windows, as Windows. You have the option of making access read-only, or full. My personal preference is to make all drives and directories read-only, with the exception of an upload folder that I give full access to. (38K)

If you share a drive, you share all files and directories within that drive. To my knowledge, you cannot explicitly unshare specific items within a larger share. For example, if I share C:, and Windows is within C:, I cannot tell it to share everything but C, unless I share all the directories as sepearate shares except for C:\Windows.

Running the Program

Upon installation, the DCC program can be accessed via the start button under: Start-->Programs-->Accessories-->Direct Cable Connection. The executable program lies under \Windows\Directcc.exe. It may be convenient to make a shortcut to the desktop.

When you run the program, you will have to specify whether it will act as the host or the client. The choice is yours. Note that the host can't view the files on the client, but the client can see all that is shared on the host. The connection is sort of one way, and I don't know why they did it this way.

If you have the option, choose your parallel ports to make the connection. They are several times faster than serial ports.

It is possible that after installing the serial ports in Windows, they don't show up as options in Direct Cable Connection. If that is the case, you can click on the Install New Ports button in the DCC program. This should bring up a little box that says Configuring Ports, Please Wait, and then show a Serial Cable on ComX. This will make a new entry in the device manager under Modem called serial cable on ComX. I have found no way to install this outside of the DCC program.

If the host asks, "Is the guest computer running," then the connection has failed. If the guest computer says "Cannot connect to the host computer," then the connection has failed. (33K)

If you have followed all of the above procedures, and are still unable to connect, then I am running out of ideas. Somewhere between the DCC program of the Host and the DCC program of the guest there is an incomplete layer. Double check your serial ports.

A Microsoft article stated that if \Windows\System\vredir.vxd is damaged or missing it can cause the "Host not found" error. To alleviate, recopy the file from your Windows 95 source disk using the extract command. Example: at prompt type: "extract D:\Win95\Win95_12.cab vredir.vxd C:\Windows\System" This assumes drive D is your CD-ROM and C has Windows. This is not the only cause of the error message.

If you get the message, "verifying user name and password," then you are close and can rule out misconfigured serial ports or an incorrect cable. Something had to be communicated in order to make the computer think that. Nevertheless, the connection can still fail after this point.

If all is setup properly, you should see the message, "verifying username and password..." within about 5 seconds of initiation. The host will then say "Connected via Serial cable on COM(x)" after about 10 seconds, but the guest will take a little longer to decide they are connected.

If the guest computer prompts you for a Windows Networking password, you must logon. (This should come up when Windows loads, but if you cancelled it there, you will see it while DCC does the handshaking.) Just make something up if you want to, but Windows needs to have a way to identify you on a network. This password is not authenticated on the host computer.

After you enter in your networking username and password, you may be prompted for a Windows Logon password. This logon does not apply to networking and DCC does not need this one.

At this point, the guest should say something like "looking for shared folders." Eventually, the guest will probably prompt you saying that it was unable to find the host computer or it's shares and you will be prompted to enter in the host computer's name. The hosts name is found under the Identification tab of the Network Neighborhood window where you entered in the computer name before.

Almost instantly after you enter the host name, you should be successfully connected. Your host's shared drives should pop up automatically but if they don't, you can click the "View Host..." button on the DCC window.

You can map a network drive to the shares for faster access within explorer. To do so, go to the menu bar, Tools-->Map Network Drive. The format for the path is \\computername\nameofshare If drive C: is shared as C on a computer named Bob, then I would type \\Bob\C for the path. The path statement is not case sensitive.

If you are copying files with the .exe extension, I highly recommend that you use the copy and paste functions, otherwise Explorer often just creates shortcuts in the destination directory. (Highly annoying) I advise copy and paste anyway.

Be sure to use the correct kind of serial cable. A lot of people don't know the correct way to do it.

Some experiments I conducted

This experiment was conducted during the summer of 1997. The most recent update of this page was in March of 1998. I will add more comments about the results, and possibly conduct more extensive tests at a later date. Until then, the comments below are several months older than the rest of the page.

The inconsistencies of these results are fairly confusing to me. I should mention that the serial cable used was 25 feet in length, the parallel cable 6, and the ethernet cable was less than 10 feet, although LAN cable should have similar results up to great lengths.

A 4.74 megabyte file transfer took 33 minutes to complete over serial cable. My average transfer rate then, was about 20 Kbps (2.5 KBps). Compare this to a 33.6 Kbps modem (4.2 KBps max) or a 14.4 Kbps modem (1.8 KBps max). Not The best, but it is something. I once waited over 12 hours overnight for a 62 meg transfer over a serial cable. The length of my cable probably causes a slower rate. (I have done it with 50 feet also.) About 6 feet is recommended. Changing the port setting through Windows did not seem to have any effect.

Isn't Microsoft Help just the best when it comes to Direct Cable Connection? I sure didn't learn this from it. Best of luck.