Which paper tape hole is bit 1?
Charles
charlesmorris at direcway.com
Thu Nov 17 20:24:12 CST 2005
Today I was hooking up my homebrewed driver board to the M-series
connector on the back of my Tally 420PR tape punch (interfaces to
my 8/A and . Fortunately, before I inserted the eight data pins
into the connector body it occurred to me that Tally and DEC might
not interpret the holes in the same order. And indeed they don't!
The paper tape has five holes on one side of the sprocket hole and
three on the other. Typical DEC terminology is Bit 1 = MSB and Bit
8 = LSB. Is that in fact how DEC labeled it?
Is the MSB on the outside of the 5-hole side or the 3-hole side?
Which hole on the tape is which?
Even more interestingly, Tally labels their punch pins as follows:
(* is the sprocket hole)
8 7 6 1 2 * 3 4 5
and I confirmed this by actual test. So much for consistency
<sigh>
-Charles
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