Direct Cable Connection

~ the obituary ~

On a Windows 98 machine in Turkey in 1999 the interesting place to poke around was Accessories, then Communications. Dial-Up Networking lived in there, which is how I got online over a 33.6k modem on TTNet. A couple of icons across sat something called Direct Cable Connection. I never had the second PC and the cable to try it with, but I opened it the way you opened everything in that menu at that age, and the first thing it wanted to know was whether this computer was the host or the guest.

What it did was turn a cable into a network. You ran a null-modem serial cable or a parallel LapLink cable between two PCs and named one of them host and the other guest. You shared a drive on the host, and the guest could then browse that drive as if it were sitting on a local network. It shipped in the original Windows 95 release on 24 August 1995 as an optional component under Communications, selectable during a Custom or Portable setup or added later through Add/Remove Programs, and it survived barely changed as far as Windows XP.

Windows Vista dropped it. Microsoft's statement to that effect is KB article 930086, last reviewed on 12 January 2007, which says that Vista "does not support direct incoming connections that either use a serial cable or an infrared link" and then puts the matter under the heading the company reserved for things it had no intention of fixing: STATUS, this behavior is by design. Vista had reached volume-license customers on 30 November 2006 and reached ordinary buyers on 30 January 2007, and the second date is when the feature actually left the machines you could walk into a shop and buy. KB 930086 itself now returns 404 and survives only in the Internet Archive.

~ the case file ~

~ how it worked ~

Two cable families, and the choice mattered. Serial meant an ordinary RS-232 null-modem cable, DB9 or DB25, nothing branded or special, and the link ran PPP over it. Parallel was the faster option and came in several grades, from the plain 4-bit cable everyone called a LapLink up to the Extended Capabilities Port and Universal Cable Module variants, with Microsoft later putting the DirectParallel name on the good ones. Microsoft never published a throughput figure for any of this. The port ceilings are the usual quoted numbers, roughly 14 kilobits per second over serial and something over a megabit on a good parallel link, which should be treated as the hardware's limit rather than a measurement of DCC.

On top of the link you still needed the ordinary Windows file-sharing stack, so NetBEUI with Client for Microsoft Networks and File and Printer Sharing was the normal recipe, though TCP/IP worked if you handed it an address and a subnet mask. The host had to explicitly share its drives before the guest could see anything, at which point the shared drive got the little blue hand under its icon, which is the detail that will bring the whole era back for anyone who ran Windows 9x.

One thing it never did was work over USB. The misconception was common enough that USB.org addressed it directly in their FAQ: two hosts cannot be joined pin to pin. Getting USB to do this required a cable with a chipset inside it, which is exactly what Microsoft eventually sold.

~ what it was for ~

The ancestor was Interlnk and Intersvr, which arrived in IBM's PC DOS 5.02 in 1992 and in MS-DOS 6.0 in March 1993, over the same null-modem and parallel cables for the same reason. They are worth keeping straight from DCC rather than treating as one lineage, and Wikipedia is blunt about it: Interlnk does not communicate with the Windows 95 Direct Cable Connection utility at all. Two incompatible answers to the same problem, eighteen months apart.

The problem itself was that a home or small-office PC in the nineties did not come with a network card. A network card was a purchase and so was the hub to plug it into, and USB flash drives were still years away. Getting a folder from one machine to another meant a stack of floppies or a cable. Anyone who had a desktop and a laptop in 1997 used DCC or LapLink's own software, and that was the entire market: people with two computers and no network between them.

~ the removal ~

Windows XP had already begun the handover with its Files and Settings Transfer Wizard, which could itself run over a DCC link. The successor was demonstrated at the Windows Hardware Engineering Conference in 2004 and shipped in Vista as Windows Easy Transfer, and it wanted a proprietary USB Easy Transfer Cable that you bought as an accessory. So the feature that had existed because networking hardware cost money was replaced by a feature that required buying a specific piece of hardware.

Windows Server 2003 held onto a direct serial incoming connection a while longer, under Routing and Remote Access rather than the consumer wizard, which makes it the last Windows to carry the capability under any name. By the time XP itself went out of support on 8 April 2014 the wizard had already been gone from current Windows for seven years, and by then home Wi-Fi and USB sticks between them had made the question it answered impossible to ask.

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