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1. General Description

Time (in mi Iliseconds)

Event

Card reader receives val id read order and reader is in II busy automatic ll state. light check occurs

0 - , - - , - - - - - - - at this time. If light check fails, the read indicator will light, the reader will switch to IInot op-

100

110

erational ll and an lIunusual end ll will be signaled to the controlling system.

---t-----i-------

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

1 and 2 are punched.

210 -01-....J....------Column 80 arrives at read station.

220

230

240

End of card is detected; card reader signals IIchannel end ll to controlling system. Card reader

returns to II ready II condition (a new SIO can be accepted if no interrupt is pending) unless the con-

troll ing system specifies command chaining, in which case the reader requests a new read order.

250

--®-Newfeedcycle enabledatthistimeifnewvalidorder present and readerstill inllautomatic ll mode.

Notes:

Feed cycle is usually approximately 47 ms but can be as long as 200 ms (in case of slippage or slight jam).

If a card has not been fed after 200 msec, the transport motor wi II hal t, the reader wi II switch to IInot op-

erational

the FEED indicator will light, and an lIunusual end

will be signaled to the controlling system.

The data bytes are transmitted, with respect to the column read time (approximatel y 2.05 ms), as shown

below.

1--2.05ms---r-160ms--l

Data available to controlling system

Col. 1

EBCDIC mode:

Transmit one byte

for each column

~ , ' - - - - - - -..... ' - - - - - - - - ' ' - - - - -

f1Jl

nn_

Binary mode:

Transmit rows 12-5

Store rows 6-9

ransmit rows

2-9

Transmit rows 12-1 plus

rows 6-9 of previous column

indicates data overrun will occur at this time if data is not accepted by controlling system.

Throat jam detection occurs 215 ms later if card jams in throat area, causing transport motor to halt, FEED

indicator to light, reader to switch to "not operational ", and an lIunusual end" to be signaled to controf-

i ng system.

Read and timing jam detection occurs 225 ms later if card jams in read and timing area.

Results in same

action as

above.

Dark check occurs at this time. If dark check fails, the READ indicator will light, the reader will switch to

IInot operational ", and an lIunusual end

will be signaled to the controlli ng system.

Stacker jam detection occurs 215 ms later if card jams in stacker area. Results in same action as

above.

Figure 5. Card Reader Event Times (Model 7121)

Programming Considerations