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1. General Description

Time (in milliseconds)

Event

o _----r---r----------

Card reader receives valid read order and reader is in "busy automatic" state.

1----1-----------

Column 1 arrives at read station. Mode change (EBCDIC to binary) will occur at

100

110

120

130

140

this time if rows 1 and 2 are punched.

Column 80 arrives at read station.

End of card is detected; card reader signals "channel end

to controlling system.

Card reader returns to

ready'. condition (a new

510

can be accepted if no in-

terrupt is pending) unless the controlling system specifies command chaining, in

which case the reader requests a new read order.

150~~-------------

Card advances from read station to stacker station.

New feed cycle begins at

this time if new valid order is present and reader is still in the lIautomatic

mode.

160+--It-------------

Card is stacked in preselected stacker or in error stacker (alternate

2).

Notes

If the feed cycle begins while the previous card is being stacked, a stacker transport jam occurring in this time

interval causes the reader to stop the transport motor, switch to IInot operational II, light the FAULT indicator,

and signal lIunusual end

to the controlling system.

Feed cycle (approximately 43 milliseconds).

The data bytes are transmitted, with respect to the column read time (approximately 1.34 milliseconds), as follows:

Column read pu Ises

EBCDIC mode:

Binary mode:

odd column even column

odd column

transmit one byte

for each column

Transmit rows 12-S

Save rows 6-9

Transmit rows 2-9

Transmit rows

12-1

plus rows

6-9 of previous column

If stacker jam occurs after new feed cycle begins, action during this interval is identical to note A. If stacker

jam occurs before new feed cycle begins, reader turns off transport motor, switches to IInot operational

state,

and lights FAULT indicator ("unusual end" is not signaled in this case).

Figure 4. Card Reader Event Times (Model

7120)

Programming Considerations