SATO D508, D512 service manual Receive Buffer CONT’D, Multi Job Buffer

SECTION 5: INTERFACE SPECIFICATIONS

5.2 THE RECEIVE BUFFER (CONT’D)

Multi Job Buffer

The printer is able to continuously receive print jobs, compiling and printing other jobs at the same time. It acts much like a "print buffer" to maximize the performance of the host and the printer.

When you are using the RS232 Serial interface, the Multi Job Buffer uses either the Ready/ Busy with DTR (pin 20) or X-On/X-Off flow control protocols. With an empty receiving buffer, the status of DTR is "high" (or an X-On status if using X-On/X-Off), meaning the printer is ready to receive data. When the receive buffer is holding 1.95MB of data (1MB from being full), DTR will go "low" (or an X-Off is sent) indicating the printer can no longer receive data. This condition is called "Buffer Near Full."

The receiving buffer will not be able to receive more data again until a "Buffer Available" condition occurs. This takes place when the receiving buffer has emptied so that only 1MB bytes of data are being held (1.95MB bytes from being full). At this time, DTR will go "high" or an X-On is sent to tell the host that it can again receive data.

All printer error conditions (i.e., label out, Time-out Error, etc) will cause the printer to go busy (DTR "low" or X-Off) until the problem is corrected and the printer is placed on-line. The printer will also be busy if taken off-line from the front panel.

SATO D508/D512 Operator Manual Page 5-3