DATAMATH CALCULATOR MUSEUM
Texas Instruments TI-620
|Date of introduction:||1974||Display technology:||n.a.|
|New price:||$ 299.95||Display size:|
|Size:||14.0" x 10.0" x 3.7"||Printer technology:||Drum impact red/black|
|Weight:||6 pounds 8 ounces||Serial No:||620-067224L|
|Batteries:||Date of manufacture:||wk 10 year 1975|
|AC-Adapter:||120V AC||Origin of manufacture:||USA|
|Precision:||12||Integrated circuits:||TMS0203, TMS0221, TMC0306, TMC0406|
|Memories:||1 + 1|
|Program steps:||Courtesy of:||Larry Corrado|
This rare TI-620 was introduced in the year 1974 and seems to be a sibling of the TI-450 and TI-500.
At first glance the TI-620 looks like a modern printing desktop calculator - but it misses the display. On top of the huge keyboard there are only four Status Indicator LED's:
|• PW: Power On
• M: Memory
• OF: OverFlow
• K: Constant
this TI-620 manufactured in March 1975 (Thanks, Larry!) is not an easy task but
from great interest. The
whole calculator is centered around the huge, self-contained printing assembly.
It was manufactured by Japanese Suwa Seikosha Co, LTD.,
better known under the EPSON brand. It has a red/black ribbon and dimensions
are 4.3" x 2.8" x 5.2". There are 15 print columns occupied, but it appears that only 13 of those are for digits and
separators; the right two columns are for op codes.
The TI-620 uses a calculator architecture based on the TMS0200 Chipset for 12-digit desktop calculators but misses the usual 12-digit display. Related calculators using this chip set are the SR-20 and SR-22. The first usage of the chip set were the TI-4000 and the Canon 121F.
The TI-620 is as of today the only calculator known using all four members of the First Generation TMS0200 Building Blocks:
TMS0200 Data Chip – Register Processor with four 16-digit Registers and seven Keyboard Scan inputs
• TMS0300 ROM Chip – 512*13 Bits Instruction Memory with serial interface to Data Chip and 13-digit display and keyboard scanning, up to 4 ROM Chips
• TMC0400 ROM/Register Chip - 512*13 Bits Instruction Memory with parallel interface to ROM Chip and two 16-digit Registers
• TMS0220 Printer Chip – Interface to two-color Drum Printer Mechanism
If you search in Texas Instruments' own "History Section" for their
first printing calculator, you'll find the TI-5050
introduced one year after this TI-620. The TI-5040
featured the first combination of a display and a printer in a desktop housing.
If you have additions to the above article please email: firstname.lastname@example.org.
© Joerg Woerner, March 26, 2002. No reprints without written permission.