coco 1


(click on picture)


Introduced    1980  
Discontinued    1982
Release Price  $399.00


        The TRS-80 Color Computer 1 was the Tandy Corporation's first color computer sold through its chain of Radio Shack stores geared for the home computer market. Tandy was an early participant in the micro-computer market with it's business line of computers, TRS-80 Models I, II, III, and IV. 

        The TRS-80 Color Computer 1, (nicknamed the 'CoCo' by loyal fans of the computer), was designed to penetrate the home market which at that time was heating up with more entries with color capabilities. The CoCo 1  was initially released with 4K or 16K of user RAM and on later models expanded to 32K. There were 3 revisions of the CoCo 1 before the release of the CoCo 2 all with distinctive cosmetic differences. The first two came in a one piece silver-gray plastic case. 

        The earliest version, which is pictured above, came with a chiclet style keyboard and only 4K or 16K of user RAM. It can be distinguished from later revisions by the position of the Radio Shack logo above the keyboard, it is not centered but shifted to the far left, and a small 4K or 16K button on the lower right corner on top of the case above the keyboard. 

        The 2nd revision retained the chiclet style keyboard and silver case, but came with a whopping 32K of user RAM. This version can be distinguished by the positioning of the Radio Shack logo in the center above the keyboard and the absence of the 16K button on the top of the case. 

        The third and final revision of the CoCo 1 saw the end of the silver-gray color case, to be replaced with a white color case and gone was the chiclet style keyboard, replaced by an improved keyboard. By this time RAM memory was  beginning to drop in price and this version of the CoCo 1 came standard with 64K.

        On the rear of the CoCo are a number of ports and pushbuttons, starting from left to right a pushbutton reset switch, an RCA type plug for RF output to a TV, a select channel output 3 or 4 slide switch, a round 5 pin DIN, ( an acronym for the Deutshe Industrie Norm ) connector port for connecting a cassette recorder for mass storage, a round 4 pin DIN connector port for connecting a modem or printer, two round 6 pin DIN connector ports for connecting joysticks, and a pushbutton off/on power switch.

         Unlike other one piece computers of the era the CoCo's power supply was built in. The norm was a large 'brick' like power module that added to the tangle of wires and confusion behind the computer. 

         On the right side is an opening for the expansion slot to insert ROM cartridges called 'Program Packs' or the disk controller for the single sided 156K Model 500 Disk Drive.

          The 4K CoCo 1 in this exhibit was acquired at a flea market complete in its original box along with a model 500 disk drive.


System Architecture



Microprocessor 6809E Standard on system board 4K (early models) or 16K
Clock speed 0.89 MHz Maximum on system board 32k (early models) or 64K
Bus type Tandy Proprietary Maximum total memory 64K
Data bus width 8 - bit Memory speed and type  
Address bus width 16 - bit System board memory socket type  
Interrupt levels N/A Number of memory module sockets  
DMA channels N/A Memory used on system board  

Standard Features


Disk Storage

ROM size 8K expandable to 16K Internal disk and tape drive bays none
Optional math coprocessor no Standard floppy drives none
Parallel port type none Optional floppy drives: yes
RS232C serial ports yes * 5 1/4 inch 156k up to 4 external
Mouse ports shared joystick * 5 1/4 inch 1.2MB no
UART chip used N/A * 3 1/2 inch 720k no
Maximum speed N/A * 3 1/2 inch 1.44MB no
CMOS real time clock N/A * 3 1/2 inch 2.88MB no
CMOS RAM N/A Hard disk controller included no

Video & Graphics



Graphics Processor   Sound Interface device  
Screen size - Col x Rows 32 X 16 Sound generation  
Resolution - Colors/High 9 / 256 X 192 ADSR capable no
Resolution - Colors/Low      
Max colors 9 Programming language  
Sprites or Missiles no Built in language Microsoft basic ver 1.1
    Built in M L monitor no

Expansion Slots


Keyboard Specs.

Total adapter slots none Number of keys 53
Number of 8/16/32 bit slots none Upper/lower case yes/yes
    Keyboard cable length N/A
Total I/O ports 2 joysticks/1 RS232c

1 cassette interface

1 game port


Physical Specs.


Environmental Specs.

* Height 3 3/4 inches Operating voltage @ 60 Hz 105 to 130 VAC
* Width 14 1/2 inches Maximum power supplied 0.26 WATTS
* Depth 13 3/4 inches Power supply output - volts  
* Weight  7 pounds 4 ounces Power supply output - amps