Panduit TDP46H - Manual (Page 68)

PANDUIT TDP4*H GMTDPH-MAN Page 6-2
Section 6: Interface Specifications
WARNING: Never connect or disconnect interface cables (or use a switch box) with power applied to either the
host or the printer. This may cause damage to the interface circuitry in the printer/host and is not covered by
warranty.
The Receive Buffer
The TDP4*H printers have the ability to receive a data stream from the host in one of two ways. The receive
buffer may be configured to accept one print job at a time or multiple print jobs. The single job print buffer is
generally used by software programs that wish to maintain control of the job print queue so that it can move a
high priority job in front of ones of lesser importance. The multiple job buffer, on the other hand prints all jobs in
the order they are received by the printer, and the order of printing cannot be changed.
SINGLE JOB BUFFER
The printer receives and prints one job at a time. Each job must not exceed 2.95 MB.
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 using the RS232C
Serial interface, the Multi Job Buffer uses either the Ready/Busy with DTR (pin 20) or X-On/X-Off flow control
protocols. See these sections for more details. 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
2.0 MB of data (1 MB 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.”