DOS directory from Windows

Does anybody know if there is a program that will let a windows computer connect to a DOS computer via a serial cable for file exchanges?

Randy BristowSenior Systems AnalystAsked:
Who is Participating?

Bucket loadsof apologies fo' stampin' on yer foot....

I have contributed much time to this issue and I truely think RandyB will finally crack it this time....

I have every faith in him or her....

RandyB has had good advice from all of us (short of knocking on his or her front door equiped with a spare cable and a port tester).

RandyB is a good and deserving member of EE having previously contributed by way of offering advice and receiving it....

I take back any comments that may have offended him or her....

In the meantime, if RandyB establishes a working and satisfactory solution to his problem then an even greater problem will be who to award his or her points the advice given has been first class.  Btw, I like the page you knocked up....

In the meantime RandyB, as an engineer, I would warn you that we don't usually stab about in the dark....

In situations like this I would:

1) test the COM ports with a null port tester
2) open the PC and confirm a good and 'clean' connection of the COM port connectors
3) copy fresh copies of interlnk and intersvr drivers onto the PCs
4) double-check Config.sys
5) test and verity the cable is good
6) double-check the null cable is connected soundly
7) check the BIOS for port configuration issues
8) if all fails, ascertain to confirm known issues with bi-direction, UART compatibility, interrupts and other resources and software port configuration issues.

It's now up to RandyB to apply the advice given....

I await the outcome....



What is the Windows and DOS versions you'll be using?
MS-DOS 6.xx shipped with the INTERLNK app which will connect computers
via serial ports and let you access and copy data from one to the other.
It works with earlier versions of DOS too, and it may be something you already have.
(filename is INTERLNK.EXE) Post back if not, or if you need something different from that.
FastLynx, Brooklyn Bridge, XTLINK and other software.
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Randy BristowSenior Systems AnalystAuthor Commented:

Randy BristowSenior Systems AnalystAuthor Commented:

I had already been playing with interlink but cant seem to get it to work. I don't know what I'm doing wrong that's why I posted the question. I put the line in my config.sys file and it is running but I can't seem to get the 2 computers to talk to each other. Maybe you have used this program before and can point me in the right direction. I would rather use this method so I don't have to install an aditional program on each computer. Thanks.


I downloaded the demo of FastLynx and got it to work fine, but the computer I want to connect to has no floppy drive so interlink would be best since it is already on the other computer. I'm basically just playing around anyway and hate to spend that much money for something I really do not need. Thaks for answering though.

You are running interlink on both computers are you?

Ensure you do not have FAT32 on the one you are copying to or you may have problems.

Here's some info on Interlink
Randy BristowSenior Systems AnalystAuthor Commented:
ok, I got it to work with a parelell cable finally but still won't work with the serial cable. Does the serial cable have to be a "null modem" like the one for the paralell port was? Let me know what you think.


By the way, that link was for Ultima
Sorry.  Here is the correct one

Yes null modem type cable.  Also check which com ports you are using.
ditto. Serial or parallel, advise you only boot diskettes in both machines. Treat one as master, provider of space, other as slave, the seeker, keep that clear. Adjust config.sys and autoexec according, on diskette only. They do differ from one to other.
Randy BristowSenior Systems AnalystAuthor Commented:
I can't seem to find a null serial cable, any ideas where to look? Also, why do you suggest the use of bootdisks?

A favourite of mine used to be Laplink

The good thing about Laplink is that it is a single executable program file that fits onto a single floppy.  

You simply connect both PCs with an appropriate cable (null modem cables) and you only need to insert the floppy into one of the PCs.  When you run the program, it will give you the choice of installing itself over to the remote PC too (straight down the wire !!!).

Ideal in your case where one of the PCs does not have access to a floppy drive.

The good thing about Laplink is that no matter which PC you first install it on or run it from, BOTH PCs are capable of taking control of either of the PCs (unlike Interlink / Interserver - where one PC is the client and the other, the server).

Laplink 3 is a single file (LL3.EXE) and is only 93KB in size.

Norton Commander is another that springs to mind.  And some years ago, there were a division among users who were split between Laplink and Norton Commander.  (I preferred Laplink as I was an XTree user, in fact, I still use it, only now, I use ZTree - the 32-bit version)

You'll find Laplink 4 at:

Check out this link (head for the NETWORKING section).  You'll find lots of usefull downloads here:

Check this out for cables:

Info on Laplink: (they failed to mention it also installs across a cable to the remote PC).

Info about DCC:


You'll find other useful stuff here:

Useful resources can be found here too:

Check out Powercopy at:

Please confirm what operating system is on both PCs and weather you'll be using DOS and/or Windows (and what versions)....

MurpheyApplication ConsultantCommented:
Use the program FX.EXE the dos version is very small (only 114 Kb) but hard to find, other versions ar downloadable (working demo) at 
It is (as far as I know) the smallest and fastest transfer utility.

Good luck

1) You can use a laplink/interlink parallel cable which is very easy to find.
2)  Use INTERLNK.EXE and INTERSVR.EXE which ship with DOS 6.22 and can be copied with a floppy onto the Win98 machine.
3)  The Win98 machine must have at least one FAT (not just FAT32) partition in order for this to work.  To see what kind of partition you have, right-click on the hard drive under the My Computer window and select properties.
You can use the DOS version of PcAnywhere which symantec is so nice to still ship on all their PCA CD's. You can direct connect via the parallel or serial ports at that point.
Randy BristowSenior Systems AnalystAuthor Commented:
I do not have a problem connecting the 2 computers using a parellel port, that works fine. I need to connect using a serial port. The serial ports are installed on both machines but I still can not get them to "talk" to each other. I used a Win98 program called FastLynx and it connected with the serial ports no problem. I just can not get interlink or laplink to connect using the serial ports. Any other ideas are welcome. I used MSD in DOS and both computers show the serial port on COM 1. This getting alittle agrivating.



You say you've "used a Win98 program called FastLynx and it connected
with the serial ports no problem." Are you just mentioning this to illustrate
that the ports are working? If you're running Windows on both machines,
you can use Direct Cable Connection. You mentioned that you
"can not get interlink or laplink to connect using the serial ports."
Which (if any) of the programs would you prefer using?

You've verified the ports are configured in the BIOS (i.e., MSD isn't mistaking one
for a modem) and both are working (e.g., sees a mouse) then are you using
a DB-9 pin serial null modem cable? If you can't find one that works (some don't)
and you want to make your own, I'll provide the wiring layout. (also 25 pin if needed)
It's essentially just reversing most of the connectors and jumping the proper pins.
If your hardware is configured properly, then it'd be a matter of
configuring the specific program (and os) you'll be using.
Please post back with whatever else you have about it.
Dear Randy.....

Not to be able to get Interlnk/Intersvr working suggests the problem is obviously either with the PC, the software or you.

To be honest with you, I don't know why you'd want to connet both PCs using a serial cable in the first place.  You've already stated you've connected successfully using a parallel cable so I presume there's no REAL need to muck about.

Messing around with COM ports and diagnosing problems used to be one of the most dreaded chores I care to remember.  I used to use debug to confirm the presence of COM ports.

Fire up debug (you'll see the debug prompt '-'). Enter the following command:

D 40:00 09

A single line of text appears such as:

0040:0000 F8 03 F8 02 00 00 00 00 - 78 03

This indicates two COM ports present.  COM1 at 03F8h and COM2 at 02F8h.

To quit debug press 'Q' and enter.

A PC without COM ports will return:

0040:0000 00 00 00 00 00 00 00 00 - 78 03

Serial is much slower than parallel.  As you raised the issue of a null serial cable.  This needs to be a 7-wire null-modem serial cable.

If you're using Interlnk/Intersvr, use the /V option if necessary.

There are lots of articles on the net getting Interlnk/Intersvr up and running so I'm not going to waste time going over it.

I note you have two PCs.  One has no floppy.  The one without a floppy has DOS installed on it.  The other PC has Windows installed on it.

To summarise, my question is this: Why do you want to connect both PCs in the first case?  I can only assume it's to exchange files from one PC to the other - as stated in your initial query.  As stated earlier, this has now been done.  It appears you are now moving the goalposts.

Next time you run into this problem, client/server software, inaccessible hardware, uncertainty over cables, differing operating systems (all the ingredients for a neat little teaser, but a bag of shite when you've got to get those files across as soon as yesterday), don't you think it would be quicker to whip out the hard drive from the non-floppy PC and whack it into the other PC as a slave and muck about 'til your hearts content?

Let's face it, you'd have saved a load of time and 'agrivation'.

Randy BristowSenior Systems AnalystAuthor Commented:
t0t0, first of all, the reason I used a parallel cable was to see if I could get Interlink to work at all. After I saw that it in fact was working, I tried to go back and get the serial port connection to work. I am trying to get this working now (at my house), so when I take my laptop to work, I can hook it into the desired computer at work, which only has a serial hookup and have it work without any problems. I TESTED it using WinME and FastLynx to see if maybe my serial cable was bad, but FastLynx did connect. But just to be absolutely clear for you, I will be using DOS on both computers with a serial connection because it is my only choice. I have also verified on both computers as I stated before that the COM ports are installed and functioning properly. I don't even have a modem in either computer. I really appreciate the help, but in the future, just because you do not understand WHY somebody would want to do something a certain way, does not mean they have a choice in the matter. So now that I've told you EVERYTHING, Interlink still does not work, so...
rin1010, I have used direct cable connection several times and it would be my choice here if I had one, but I don't. Yes, the WinME part was just to illustrate that they were actually working. I would prefer to use interlink because I would not have to copy any files to the other computer. I would really appreciate the pin diagram if you get the chance, it'll have to be 9 pin to 9 pin. And thanks to everyone again.

MurpheyApplication ConsultantCommented:
So my advise to use Fastlynx was the good advice... Your initial question is solved so.....

Stay using FastLinx, it is faster then interlink or laplink and runs on Your system without any problem..

Your welkom.
Okay, I see where you're coming from....

Right, so you have a PC at work and which you want to connect a laptop to in order to exchange files.

Which machine does not have the floppy, the PC at work or your laptop?

Which machine has Windows installed (and what version?), the PC at work or the laptop?

What version is the DOS on BOTH machines?

Do you have a serial null modem cable?  If so, is ALL the pins connected or is it at least a 7-wire cable?

How many COM port connections do you have on BOTH machines (you might only have one on the laptop for example) and which ones are you using?

What are the addresses of the COM ports on both machines?

Can you confirm that the COM ports are enabled in the BIOS of both machines?

Can you verify the interrupts both machines use for the COM ports?

Do any of these machines have ANY other serial devices attached such as a mouse?  If so what device and which machine?

What make and model are the PC and the laptop?

(A difficult one) Can you confirm the UART on both machines.  Is it an older type say, 8250 UART or a 16550 variety?

You say you've gotten FastLinx to work, was this on the two machines in question (and, are you saying the COM ports on BOTH machines tested okay)?

Look at the start up files on both machines and note any references to any third party programs or drivers that might be hooking into any of the COM ports, interrupts used by the COM ports or addresses used by the COM ports.  Also, see if the DOS MODE command is not used to reconfigure any of the COM ports.

In fact, if need be, used the DOS MODE command to set both COM ports equal, such as parity etc.

Don't give up on Interlnk/Intersvr because I used to use them quite frequntly when needed when they were included with DOS.  I know they DO actually work.

Review the issues above, reply to this message and let's take it from there....

If need be, we'll review the syntax.... can you confirm how you are running Interlnk abd Intersvr?
btw, here's a url for pin-outs for the serial null modem cable



You say you'll "be using DOS on both computers with a serial connection"
and that you'd "prefer to use interlink..." And you know both serial ports function
and I presume you've successfully installed the INTERLNK.EXE device driver
from CONFIG.SYS and are using the correct INTERLNK-INTERSVR syntax.

I'm seeing the MS-DOS Help application containing considerable info about it,
including a serial cable wiring spec which MS says works with InterLnk...
This is from some of the MS-DOS Help notes on it:
"Three wires are required for data transmission;
Ground-Ground, Transmit-Receive, and Receive-Transmit...
Seven wires are required if you want to use the remote copy feature."

This is an edited version of their 9-pin flavor:

  Pin 2  (RD)  <---->  (TD)  Pin 3
  Pin 3  (TD)  <---->  (RD)  Pin 2
  Pin 4  (DTR)  <---->  (DSR)  Pin 6
  Pin 5  (SG)  <---->  (SG)  Pin 5
  Pin 6  (DSR)  <---->  (DTR)  Pin 4
  Pin 7  (RTS)  <---->  (CTS)  Pin 8
  Pin 8  (CTS)  <---->  (RTS)  Pin 7

But that's not the preferred method of wiring a 'null-modem' serial cable...
It doesn't show Pin 1 (Carrier Detect) connecting to Pin 4 (DTR)...
Pin 9 normally isn't used, but Pin 1 should go to Pin 4...
That may create a connection and perhaps all that's needed...
I've had problems when DCD wasn't used but not necessarily with InterLnk...
As noted, I edited the above, but the formatting may not be clear
once it's pasted into the EE page...
Here's a legend I made for the pin assignments:

   1   DCD  =  Data Carrier Detect
   2   RD  =  Receive Data
   3   TD  =  Transmit Data
   4   DTR  =  Data Terminal Ready
   5   SG  =  Signal Ground
   6   DSR  =  Data Set Ready
   7   RTS  =  Request to Send
   8   CTS  =  Clear to Send
   9   Ring  =  Ring Indicator

Was putting together some other notes and info for you on the pinout
for the DB-9 serial female connectors but it's tough describing
without format option control so I just made a page out of it
having a couple of diagrams and probably more legible
information about it... I've placed it on a server and
I'll append the url if you want to look at it.

If you think it might be software error, run the DOS Help app
and check out the InterLnk topic...
Hopefully this will get it going, but post back if not,
or if you need more about it like the Help pages or whatever...
Here's the url of the page having more info on it:


Don't you mean "installed the Intersvr device driver from Config.sys"?

Hmmmm... I still favour the 7-wire type.... never know when it's gonna come in handy (ideal for RandyB's situation where a PC has not floppy)

  INTERLNK.EXE is the device driver...
  It first has to be installed from CONFIG.SYS
  to use the INTERLNK and INTERSVR commands...

Core!.... You're quick!....

Forgive me for asking you to confirm that.... only I didn't want RandyB to be confused with the article I posted him at:

This says:

- Copy the intersvr.exe to the source computer (ie. the computer where your files are)

- Edit the config.sys file in the source computer to add the line device=intersvr.exe        
  (if you copy the file to a subdirectory change this line to suit)

- Restart the computer and go to the DOS mode or Command prompt mode

- Start the other computer also in the DOS mode or (Command prompt)

- Run Interlnk.exe in the other computer (client)

Randy BristowSenior Systems AnalystAuthor Commented:
ok t0t0, I do not have the needed supplies to make up the cable right now but i am going to award the points now because I now know more than I ever wanted to about serial ports and just want the topic closed. I am sure this will remedy the problem anyway. Yes it is very hard to decide who to give the points to but I did it in a very fair manner (coin flip), and will award points to rin1010 if he would like. Thank everyone again for the help. I will post if......err when I get it working.


Yes, Randy, I'd like that... And thanks!  A coin flip, eh?
My lucky day? Glad you flipped before Friday the 13th!

But really, hope the info is useful... And definitely post back
when you get it going or if you have anything else about it...
Glad to provide the syntax, notes and examples if needed...


Was the answer you accepted what you intended? I see my handle appears
at the top of that comment and wondered if perhaps you thought it was mine...
(Or maybe it was Friday 13th where you are, lol...?)
No problem if you did another coinflip or whatever, and my apologies if I misunderstood...
Just curious as to whether that was your intent...

Also a note regarding your comment about not having "needed supplies to
make up the cable..." I know it's occurred to you that a pin to pin continuity test
will indicate how your current cable is wired... If it's not wired as null,
you could use that cable, cut it in half, identify the wires with the continuity tester
if necessary and splice each to its corresponding pin.
Also, a serial connector from an old mouse having the appropriate number of wires
could be spliced to Y off from your existing cable,
leaving its current pinout and connectors intact and allowing you to use it either way.

Anyway, just posting to mention that about the cable and inquire whether you meant to
"award points to rin1010" or otherwise...
Also, please post back with results when you get it working...
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