covox speech thing

4 Articles

WFW 3.11 running on a Thinkpad T400

Windows For Workgroups 3.11 In 2018

May 15, 2018 by 61 Comments

It’s been 25 years since Microsoft released Windows for Workgroups 3.11. To take a trip back to the end of the 16-bit era of operating system, [Yeo Kheng Meng] got WFW 3.11 running on a modern Thinkpad.

To make things difficult, a few goals were set for the project. Obviously, this wouldn’t be much fun in a virtual machine, so those were banned. A video driver would be needed, since WFW 3.11 only supports resolutions up to 640×480 in software. Some basic support for sound would be desirable. Finally, TCP/IP networking is possible in WFW 3.11, so networking hardware would allow access modern internet.

[Yeo Kheng Meng] accomplished all of these goals on a 2009 Thinkpad T400 and throughly documented the process. Some interesting hacks were required, including the design of a custom parallel port sound card based on the Covox Speech Thing. Accessing HTTPS web servers required a man-in-the-middle attack to strip SSL, since the SSL support on WFW 3.11 is ancient and blocked by most web servers today.

If you want your own WFW 3.11 laptop, the detailed instructions will get you there. [Yeo Kheng Meng] has also provided the hardware design for the sound card. You can watch a talk on the process after the break.

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Making A Covox Speech Thing Work On A Modern PC

January 17, 2018 by 52 Comments

Long ago, when mainframes ruled the earth, computers were mute. In this era before MP3s and MMUs, most home computers could only manage a simple beep or two. Unless you had an add-on device like the Covox Speech Thing, that is. This 1986 device plugged into your parallel port and allowed you to play sound. Glorious 8-bit, mono sound. [Yeo Kheng Meng] had heard of this device, and wondered what it would take to get it running again on a modern Linux computer. So he found out in the best possible way: by doing it.

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Error: LP0 On ????

April 25, 2017 by 63 Comments

You don’t need fancy ICs and DACs to build a sound card for a PC. As [serdef]’s build over on hackaday.io shows, all you really need is a bunch of resistors. [serdef] built a clone of a sound card released for PC in the 80s, but with a few improvements. This mess of resistors features the best 8-bit sound you can get with a low-pass filter, volume divider, and a handy DB-25 connector.

The design of this LPT0 sound card is pretty much the same as when it was introduced to the world as the Covox Speech Thing. This ‘sound card’ was designed to clip onto the parallel port of a computer and send the 8-bit I/O of this port through a resistor ladder. Plug a pair of speakers into this thing, and you have a sound card that is completely made out of resistors. It was cheap, and in the demoscene it was popular.

There are a lot of amazing demos out there using this resistor DAC thing, and [serdef] has videos of his project playing a lot of them. You can check that out below.

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The LPT DAC

September 29, 2014 by 41 Comments

About 30 years ago, before every computer had CD quality audio built in, audio cards and chips were technological marvels. MIDI chips, FM synthesis, and synths on a chip reigned supreme but one little device – just a handful of resistors – sounded fantastic. it was the Covox Speech Thing, a simple resistor ladder wired up to the parallel port of a computer that would output 8-bit audio to an external amplifier. [FK] recently built his own Covox (Czech, Google translatrix) with just 18 resistors, and the results sound fantastic.

Instead of fancy chips, the original Covox Speech Thing used the 8 bit parallel port on a PC. Back in the olden days, this was the fastest way to get digital data out of a computer, but since it was digital only, a DAC was required to turn this into audio. A simple resistor ladder was sufficient, and this hardware was eventually supported by the old DOS games from Sierra and Id.

[FK] has a demo of this LPT DAC available here, but we’re not thinking that link will last long. If anyone has a better link, leave a note in the comments and we’ll update this post. Thanks [beavel] for sending this in.