Radio Shack TRS-80 CR-510, Руководство по эксплуатации

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Card Reflectance
Cards shall have a minimum reflectance of 70% (measurements must be made at the near infra-red
end of the spectrum).
Printing Ink
Card Body Ink may be any color (Sinclair and Valentine J6893 Red etc.) and it must maintain
a minimum reflectance of 70%.
Timing Marks Ink must be non-reflective (PMS Black, etc.) and maintain a maximum reflectance
of 20%.
Timing Marks
The Card Reader will read cards that have data aligned with the timing marks. Timing marks are
positioned along the left side of the card (see Figure 10). For optimum chad-scan, the marks must be
centered on the chad column and should be as wide as the chad boundaries.
Timing Mark Height — 0.120 ± 0.025 inches
Timing Mark Width Widths may vary from 0.024 to 0.25 inches. Best results are obtained when the
timing mark width and the chad width are approximately the same.
Space Between Timing Marks must be a minimum of 0.070 inches.
First Timing Mark Location — 1st mark must be 0.077 inch (minimum) from the leading edge of
the card.
Chad Location
The Chads (each row) must be centered at 0.25 inch intervals across the card from card edge to edge
as shown in Figure 9.
The center of chad 12 and chad 9 must be 0.25 of an inch from the card edge.
Tolerance is ± .005 inches unless specified. This card and specifications are designed for reading
during the timing marks.
How the Card Reader Works
The Card Reader reads the data by reflecting light from a lamp off of the cards and onto a series
of photoelectric cells. The unit reads one column at a time, translates the data into a format (specified
through software), and stores the data in a buffer.
When the card has been read, the data is sent byte-by-byte out the Serial I /O Port of the CR-510 into
the Serial I/O Port of your computer.
Commands and echoed data are sent from your computer to the CR-510. You can instruct the Card
Reader to transmit its current "status" along with the card data that is transmitted. The status is
a two-byte ASCII string consisting of a status code followed by a comma.
If needed, you may instruct the Card Reader to expect an "echo" of the data it transmits to the
computer. With this option, you can verify that what was received by your Computer was what was
sent by the Card Reader.
Note: Your driver must echo the data back to the unit. (See Data Transmission Integrity.)
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