The U.S. company SWTPC started in 1964 as DEMCO (Daniel E. Meyer Company). It was incorporated in 1967 as Southwest Technical Products Corporation of San Antonio, Texas. They produced a wide variety of electronics kits, and later complete computer systems.
In the 1960s, many hobbyist electronics magazines such as Popular Electronics and Radio-Electronics published construction articles, for many of which the author would arrange for a company to assemble a kit of parts to build the project. Daniel Meyer published several popular projects and successfully sold his kits. He soon started selling kits for other authors such as Don Lancaster and Louis Garner. Between 1967 and 1971 SWTPC sold kits for over 50 Popular Electronics articles. Most of these kits were intended for audio use, such as hi-fi, utility amplifiers, and test equipment such as a function generator based on the Intersil ICL8038.
In 1972 SWTPC had a large enough collection of kits to justify printing a 32 page catalog. In January 1975 SWTPC introduced a computer terminal kit, the "TV Typewriter", or CT-1024. By November 1975 they were delivering complete computer kits based on Motorola MPUs. They were very successful for the next 5 or so years and grew to over 100 people. Most of the companies that were selling a computer kit in 1975 were out of business by 1978. Around 1987, SWTPC moved to point of sale computer systems. The original company was terminated about 1990 and became Point Systems. This new company lasted only a few years.
Microcomputer pioneers 
When microprocessors (CPU chips) became available, SWTPC became one of the first suppliers of microcomputers to the general public, focusing on designs using the Motorola 6800 and, later, the 6809 CPUs. Many of these products were available in kit form as well. SWTPC also designed and supplied computer terminals, chassis, processor cards, memory cards, motherboards, I/O cards, disk drive systems, and tape storage systems. From the older "TV Typewriter" design a Video terminal had evolved the CT-64 terminal system, which was an essential part of many early SWTPC systems. Later a more intelligent version of this terminal, the CT-82, was introduced, and a graphical terminal the GT-6144 Graphics Terminal. Still later a SS-50 bus plug-in board, the "Data Systems 68 6845 Video Display Board" was introduced, and a keyboard could be connected to this board. With this solution an external terminal was no longer needed.
SWTPC's SS-50 backplane bus was also supported or used by other manufacturers: (Midwest Scientific Inc, Smoke Signal Broadcasting, Gimix, Helix, Tano, Percom Data, Safetran), etc. It was extended to the SS-64 (for the 68000 CPU) by Helix. SWTPC also designed one of the first affordable printers available for microcomputer users; it was based on a receipt printer mechanism.
Technical Systems Consultants, first of West Lafayette, Indiana (ex Purdue University) and later of Chapel Hill, North Carolina, was the foremost supplier of software for SWTPC compatible hardware. Their software included operating systems (Flex, mini-FLEX, FLEX09, and UniFLEX) and various languages (several BASIC variants, FORTRAN, Pascal, C, assemblers, etc.) and other applications. Other software, from third parties, included Introl's C compiler, Omegasoft's Pascal compiler, the Lucidata Pascal system (from Cambridge, UK), and assorted spread sheets and text processors. By about 1980, TSC had developed a Unix-like multi-user, multi-programming operating system (UniFlex), for 6809 systems with DMA 8" floppy disks and extended memory. Several of TSC's languages were ported to the UniFlex, as was the Lucidata Pascal system.
SWTPC was a pioneer of open source software. Their software catalog included the TSC software, and software from many other sources (including SWTPC itself). Much of it was available in source code—for a higher cost.
Product gallery 
Click the images to enlarge.
Universal Strobe (1968)
Stereo preamplifier (1969)
Digital Measurements Lab, Frequency Counter Module (1970)
Function Generator based on Intersil ICL8038 (1973)
- SWTPC product history website – By Bill Dawson and Michael Holley
- SWTPC page at Old Computer Museum
- SWTPC M6800 at PC-History.org
- SWTPC M6800 specs and pictures at Erik Klein's computer page
-  Flex User Group Home pages sponsored by Micheal Evenson
-  6800/6809 Flex Emulator for x86 based Microsoft operating systems
- Exorsim Open source 6800 Flex (and Motorola Exorciser) Emulator for Linux/Cygwin
- SWTPC 6800 in Vintage Computer Archive
- SWTPC 6809 in Vintage Computer Archive