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

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Under this format, the Card Reader expects one marking per field. Byte 1 consists of the ASCII code
of the character represented by the marked row of Field One. Byte 2 consists of the ASCII code of
the character represented by the marked row of Field Two. For example if Row 0 is marked, then
Byte 2 is equal to 67 (the ASCII code for "C").
If there are no row markings in a field, then the corresponding byte equals 63 (the ASCII code
for "?'). If there is more than one row marking in a field, the Card Reader looks for the most
dominant marking. If it cannot determine which is dominant, then the corresponding byte is returned
as 62 (the ASCII code for ">").
Feed Mode Commands
CFD
Continuous FeeD)
Puts the Card Reader into the Continuous Feed Mode.
DFD
Demand FeeD
Puts the Card Reader into the Demand Feed Mode.
SFD
Single FeeD
Puts the Card Reader into the Single Feed Mode.
PIK
PIcK card
Initiates a card read operation (when in the demand feed mode).
Status/Specification Commands
STA
STAtus
Sends the Card Reader Status to the Computer. Before sending the status, the Card Reader delays
90 milliseconds so that the computer can prepare to receive the incoming data.
RTX
ReTransmit
Retransmits the data from the last card read, regardless of any new commands (for example, a
change of format is NOT reflected in the new data). Before sending the data, the Card Reader delays
90 milliseconds so that the computer can prepare to receive the incoming data.
ECO
ECho Off
Disables the echo mode of operation. That is, characters sent to the computer are not echoed back
to the CR-510.
EC1
ECho On
Enables the echo mode of operation. All characters sent to the computer must be echoed (transmitted)
back to the CR-510. If echoed data are not received by the CR-510 within 4 seconds after
transmission, an "echo error' will occur.