DATAMATH CALCULATOR MUSEUM

Frontier Calculator Integrated Circuits

Shigetoshi Takahashi established in January 1961 Eiko Business Machine Co., Ltd., a manufacturer and distributor of electric adding machines. End of 1968 Eiko introduced with the Unitrex IC8 their first electronic calculator, based on SSI (Small Scale Integration) DTL (Diode-Transistor Logic) Integrated Circuits manufactured by Mitsubishi and a 96-bit Ferrite Core module for its data registers. A unique feature of the Unitrex IC8 is the indicator for negative numbers with all digits on the left of the result showing the minus sign. A simple operation like [1] [+] [2] [-] would result in displaying '-------1'.

Mr.Takahashi founded in 1971/1972 two companies in the United States, Eiko International and Unitrex of America, respectively and invested in Cal-Tex Semiconductor, Inc., a newly formed company focused on design and manufacturing of Custom LSI (Large Scale Integration) MOS (Metal–oxide Semiconductor) chips for electronic calculators.

Eiko introduced its first desktop calculator using LSI MOS technology, the Unitrex 1200, in December 1971. It was built around Cal-Tex's first commercial product, the CT5001 single-chip calculator circuit. Although the reasons for the rift between Eiko and Cal-Tex remain unclear, Mr. Takahashi went on to found Frontier Inc. in 1972 together with Mr. Chen in Costa Mesa, California, to design its own calculator chips.

The first product developed by Frontier was the FR1001, a replacement for the CT5001 used in the Unitrex 1200 desktop calculator and its many OEM variants. It was soon followed by the FR1003, which replaced Cal-Tex's CT5005 used in the Unitrex 1200M.

Subsequent designs from Frontier were intended for portable handheld calculators, featuring 8-digit or even 6-digit displays rather than the 12-digit displays used in desktop models.

Frontier Calculator circuits

To date, we have identified seven different calculator chips developed by Frontier.

Type	Year	Function	Calculators	Comments
FR1001	1973	Desktop	Unitrex 1200K (Type 47)	[+=] [−=] keys, 12 digits, Fix-DP [0...4], MD Constant Adding Machine Logic
FR1003	1973	Desktop	Unitrex 1202M	[+=] [−=] keys, 12 digits, Fix-DP [0...6], 4-key Memory Adding Machine Logic
FR1005	1973	Basic (Panaplex)	Unitrex 800K, Privileg 800K	[+=] [−=] keys, 8 digits, [RV] [K SWITCH] Adding Machine Logic
FR1006	1973	Basic (Panaplex)	Unitrex 800D, Privileg 800D	[+] [−] [=] keys, 8 digits, Float/Fix-DP [2] Chain Logic
FR1012	1974	tbd	tbd	40-pin Plastic DIP
FR1013	1974	Basic (LED)	Unitrex Micro M6	[+] [−] [=], 6 digits, 3-key Memory, MDAS Constant
FR1106	1974	Basic (LED)	Unitrex Mini 8, Intertronic Mini 8	[+] [−] [=] keys, 8 digits, MDAS Constant Chain Logic

In September 1977, Commodore International Ltd. (Bahamas) acquired Frontier, Inc. for approximately $10 million.

If you have additions to the above article please email: joerg@datamath.org.