Sita Msr Buffered Operation - Access ATB420 Series Service Manual

Access keyboards ATB 420/421 Multi-Function Keyboard Product Specification and Service Guide
The ATB420/421 will not decode other Bar Code symbologies.
The Bi-Color LED will show Green for one second upon transmission of the Barcode message to
the Host and the Sounder may sound if enabled .
5.5

SITA MSR Buffered Operation

The ATB420/421 has two modes of operation when Data read is read by the MSR reader. Buffered
mode only applies to MSR data. Bar Code and OCR data reads are always transmitted
immediately.
5.5.1 Un-Buffered Mode
In Un-Buffered mode, MSR data is transmitted immediately after the magnetic document is swiped.
5.5.2 Buffered Mode
In Buffered mode, the MSR data is stored by the ATB420/421 pending a command from the Host
to transmit or discard it.
Once a valid set of MSR data is Buffered, any further MSR swiped data is ignored until the Buffer is
empty. If a Bar Code or OCR document is read then the Bar Code or OCR data is transmitted
immediately and the MSR Buffered data is discarded.
5.5.3 Un-Buffered and Buffered Command Protocol
The ATB42/4210 will initialise in Un-Buffered mode.
In order to change to Buffered mode the Host must transmit the following sequence:-
<SOD1><STX><ESC> 04DH 03BH 042H <ETX><EOD1>
No acknowledgement is issued by the ATB420 to this command.
The keyboard is changed back to Un-Buffered mode by the Host transmitting the following
sequence:-
<SOD1><STX><ESC> 04DH 03BH 055H <ETX><EOD1>
In order to solicit data from the ATB420/421 when in Buffered mode the Host must issue the
following sequence:-
<SOD1><STX><ESC> 049H <ETX><EOD1>
If the ATB42/421 has buffered data it will transmit it in the format described in Section 4.4.1 and
then clear its buffer.
If no data is buffered the ATB420/421 responds with the following sequence:-
<SOD1><STX><ESC> 052H <ETX><EOD1>
to indicate no data in Buffer.
The ATB420/421 buffer may be "Flushed" (data discarded) if the Host issues the Flush Buffer
command sequence:-
<SOD1><STX><ESC> 052H <ETX><EOD1>
No response is sent back by the ATB420 to this command.
If the ATB420/421 receives a command that is not recognised or receives a buffered mode
command while in un-buffered mode, the ATB420 will respond with the sequence:-
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