Welcome to part 3 of my SepTandy Spectacular. In the last post I jumped back to 1977 to talk about The TRS-80, and in this post i'm going to talk about The next computer in the history of Tandy Radio Shack, The Tandy TRS-80 Color Computer, also known under the affectionate nickname the CoCo.
The Tandy TRS-80 Color Computer (1980).
Released in July, 1980, the Color Computer was (as the name suggests) The first Radio Shack computer to have color graphics and sound, at a retail price of under $400, it was attractively inexpensive which was appealing to a lot of customers.
But what was gained in price, was lost on software companies interest in the system due to Radio Shack's licensing policies. So there was very few recognizable software titles available for the CoCo. Think about it like a Chromebook from the 80s, A computer that could be capable of doing a lot of things, but fell apart when it came to third party software.
Actually, that description isn't that far off considering the CoCo's development story, which traces back to 1977. Around the same time they introduced the TRS-80 Model 1, Tandy were working on a experimental computer terminal project with the Kentucky Cooperative Extension Service and the University of Kentucky College of Agriculture.
Codenamed Green Thumb, the goal was to design a low cost Videotex terminal that could connect to a tv set and a phone line that would allow access to near-real-time agricultural information for farmers, ranchers, and others in the agricultural industry. To design the hardware, Tandy teamed up with Motorola, Who came up with a design using their then new 6847 Video Display Generator chip and a 6809 microprocessor.
By 1978, Motorola had a working prototype, Unfortunately, It contained too many chips to be commercially viable. Motorola responded by creating a custom chip that could integrate the functions of many smaller chips into one, Resulting in the 6883 Synchronous Address Multiplexer or SAM for short. The terminal was finally released in the Spring of 1980 as the Agvision terminal, which was also sold by Radio Shack as the VideoTex terminal.
But with the rise of home Microcomputers like the Atari 400, the Ti 99/4, and the upcoming Commodore VIC-20, Tandy realized they needed to come out with a computer of that type to compete in that field, and since the Videotex terminal already had enough hardware to make a capable color computer, All Tandy had to do was remove the internal modem, add I/O ports for things like cassette storage and serial ports, and replace the communication software with a standard BASIC ROM. The result was the Color Computer launching on July 31st, 1980, at a retail price of under $399 for a unit with 4K of RAM or $599 for a unit with 16K.
.png)
It was an unbelievable price for a computer at the time! especially considering the TRS-80 line was selling for thousands of dollars, and its nearest competitors, the Apple II+ and the Atari 400, sold for around $1500 and $500.
Inside the box was a registration card offering a 6-month subscription to Radio Shack’s Microcomputer News periodical, a 31 page TRS-80 Color Computer Operation Manual offering, A 162 page Getting Started with Color BASIC guide, the required cables, and of course, the computer itself.
The machine itself is an all in one unit, much like its predecessor. However, unlike its predecessor, it doesnt use a mechanical keyboard but rather a chiclet keyboard. While having a chiclet keyboard is common on computers today, back then it was somewhat rare to see a chiclet keyboard on a home computer. Mostly because chiclet keyboards back then were terrible! Unlike modern chiclet keyboards they don't use rubber domes or scissor switches, instead they were typically a membrane with a sheet of rubber keys over it, which is where their name comes from. The CoCo does at least use plastic keys instead of rubber which does help a little.
On the right side of the machine there is a slot for ROM cartridges, which Radio Shack called “Program Paks.”
On the back there's the reset button, the RF out so you could connect it to a tv set, the accompanying channel selector switch, a 1500 baud cassette interface, an RS232 serial port, two joystick ports, and the power button.
The RF out is really is the only video output option, as there is no RGB, s-video,or even composite without modification. Not much of a problem at the time though as most tvs didn’t have any other video ports besides RF.
Although Radio Shack did sell their own “Color Receiver” TV with TRS-80 branding, You could just use just any standard tv. Which is a good thing as I've never seen a photo of one outside Radio Shack's catalogs and advertisements.
The original “Color Receiver” TV Monitor in the 1981 Radio Shack catalog.
Powering up the machine, you get dropped into Extended Color BASIC where you're greeted with a READY prompt. once again you can type in BASIC programs to do what ever you want and to be consistent, i'll type in the obligatory HELLO WORLD! program.
There were three versions of BASIC for the CoCo, Color BASIC, Extended Color BASIC (which is what we're looking at now obviously), and Disk Extended Color BASIC. All of these were versions of Microsoft BASIC specifically spawned from Microsoft BASIC-69, a version of Microsoft BASIC designed to run on the Motorola 6800 series of microprocessors. Tandy licensed BASIC-69 from Microsoft and used it to form the basis for Color BASIC 1.0 which shipped with the original 4k Coco's on launch day with Extended Color BASIC following shortly afterwards.
Much like the TRS-80 Model I, the main source of software for most users came from typing in programs from books and magazines and there were various magazines for the CoCo such as Hot CoCo, which typically had several BASIC games and programs for users to type in.
Much like the TRS-80 Model I, the main source of software for most users came from typing in programs from books and magazines and there were various magazines for the CoCo such as Hot CoCo, which typically had several BASIC games and programs for users to type in.
However, with the introduction of the CoCo, we get the Program Pak ROM cartridges. Which was a good idea to include for two reasons, A, people were already familiar with cartridges from their exposure to video game consoles like the Atari 2600 and the Mattel Intellivision, and, B, The software was instant access. So you could plug in a game, power on the computer, and your software was ready to go, no commands required.
These Program Paks typically sold for between $25 and $40 and contained various types of software from games, to educational software, to business applications.
The Program Paks offered in the 1981 Radio Shack catalog.
There was even an Audio Spectrum Analyzer for the CoCo! That's right! There was a cartridge that you could plug into your CoCo, pipe music from the cassette port, and have it displayed on the screen. So you could do music visualization and spectrum analysis in 1981! How cool is that?!
Anyway, as you can tell from the photo above, Radio Shack typically sold these inside little cardboard boxes, along with an instruction manual doubling as box art for each title.
For storage, The CoCo can use the same cassette cables and recorders as the TRS-80, as well as the same CLOAD commands in BASIC.
Much like the TRS-80, Cassettes were really the only storage medium the for the CoCo. However, it wouldn't be long until floppy disk capability became available. Starting in 1981, with the introduction of the TRS-80 CoCo Controller cart, sold with a disk drive for a retail price of $599 as well as extra drive for $399.
.jpg)
The TRS-80 CoCo Controller cart.
This plugged in to the cartridge port and connected to a Mini Disk Drive, providing access to 156K single-sided 5.25” floppy disks, each with an edge connector around back that could allow you to daisy chain up to four disk drives to access 624 kilobytes of storage.
.jpg)
The TRS-80 CoCo floppy drive.
And if you wanted to load any carts without taking out the floppy controller, in 1983, Radio Shack introduced the TRS-80 Multi-Pak Interface, a sidecar add-on allowing you to have four switch-selectable expansion slots, which retailed for $180.
And nowadays you can get things like the CoCo SDC, which provides an SD card interface that plugs into the expansion port running with SDC Explorer, allowing you to skip the directory, loading, and execution commands and boot whatever you like straight from the main menu.
As for joysticks, Unfortunately, they're not that great. These were sold in a pair of two for $24.95. these were two analog, single-button, non-centering sticks, with a 6-pin DIN connection. while not unusable, they do have problems such as the fire button being at the top and the non centering stick's are not ideal for some games.
The CoCo Deluxe Joystick.
Other add-ons and peripherals included serial dot matrix and electrostatic printers, external modems, speech modules, graphics tablets and many more.
%20(3).png)