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Singer/Friden 1203 Desktop Calculator
The Singer/Friden 1203 shows that in the years between 1970 and late 1973 (when this particular machine was made), Singer had quite an impact on changing the 'feel' of the old Friden design practices. The 1203 is a strange exercise in styling -- very 'space-age' looking compared to its earlier predecessors which had strong signs of the much more conservative Friden style associated with them. The 1203, as compared to earlier machines also has much more plastic in its construction versus the use of metal internal structures, keyboard bezels, and keyboard assemblies of the earlier Friden and Singer/Friden calculators.
Inside the Singer/Friden 1203
The 1203 uses a single Rockwell-made
LSI (A4540) to provide the calculating intelligence of the machine. This is
in contrast to earlier Singer/Friden (like the
Singer/Friden 1114, 1115, and
1117) calculators, which used Hitachi
chips exclusively.
The 1203's Panaplex Display in Opreation The 1203 is a pretty standard
office style four-function desk calculator, with 14-digit capacity.
The display is a Burroughs Panaplex II display, with 16 elements.
The display is driven a combination of discrete transistor drivers for
the segment lines (9 lines, 7 for the seven segments of each digit, one
for decimal point, and one for the 'comma' indicator), and three Sprague
UHP 491 high voltage driver chips for digit drivers.
The left-most display element, while it contains a fully-formed digit
element, is never used. The right-most element, again a fully-formed
digit, is used to indicate a number of status conditions. The upper
horizontal bar of the 7-segment digit in this 'status' location indicates that
memory register one contains a non-zero number. The middle horizontal
bar indicates if the number in the display is negative, and the bottom
horizontal bar indicates that memory register twi has non-zero content.
In the event of an overflow condition, this digit position lights up
an "E". When the "E" indication is given, a single press of the "CLEAR"
key clears the overflow condition, but leaves the display intact, allowing
further calculation. Pressing the "CLEAR" key twice clears the whole
machine (except for the memory registers). The display also shows 'commas'
at every third digit in front of the decimal point to make reading large
numbers easier. The Singer/Friden 1203 has two memory registers, with
"M+" and "M-" keys to add or subtract the content of the display to/from
the memory register. There are two keys for each memory register related
to recalling the content of the memory register to the display. The "MS"
key recalls the memory register to the display, leaving the memory register
intact, while the "MT" key recalls the register to the display
and clears the memory register. A three-position switch on the keyboard panel
controls summing modes for the memory registers. In the "OFF" position,
no memory summing occurs. When set to the "Sigma 1" position,
the result of any multiply or divide operation is automatically added
into memory register 1 when the result is calculated (by pressing
another function key (multiply, divide, %), or by pressing '='). When the
switch is set to the "Sigma 1,2" position, the first operand of a
multiply or divide operation (multiplicand or dividend) is added to
memory register 2 as soon as the multiply or divide key is pressed, then
the resultant answer is added into memory register 1 when the result
is calculated. The 1203 also has a "%" key, used in conjunction
with the multiply or divide keys to calculate percentages. An example
would be doing a mark-up calculation; let's say an item at a store
currently costs $1.89, and the store manager has been informed
that the item has had an 8% price increase. The manager
wants to know what the new price should be. On the 1203, it's a simple
matter: 1.89 X 8 % (which displays .1512, which is 8% of 1.89), then
press the "+" key to perform the mark-up, resulting in 2.0412, or
$2.04 for the final price. The same operation, but with pressing
the '-' key, performs a 'mark down' operation. The machine
also has a "Change Sign" key which toggles the sign of the number
in the display, and an "R" key which swaps the arguments of multiply
or divide operations. The calculator provides automatic constant
for all four functions. The 1203 has a rotary switch on
the keyboard panel which selects the method of decimal point handling
the machine uses. Fixed-point operation can be set at any position from zero
to seven digits behind the decimal point. An "F" position selects full-floating
point operation, and a "+" position selects a 'dollars and cents' mode
with 2 digits behind the decimal point. An "N" position doesn't seem
to have any different behavior than floating decimal mode. The keyboard
is of surprisingly high quality, using magnet-activated micro-switches.
