Printronix P7000 User Manual page 97

Dataproducts (Standard) Submenu
For example, if the printer is printing a job from the serial port, and
then receives a second print job from the parallel port, the data from
the parallel port will "trickle" bit by bit into the printer buffer to
prevent a timeout error from being sent back to the host connected
to the parallel port.
The selected value is the time that the printer waits before getting
the next byte of data from the host. The Trickle Time value should
be less than the host time out value, but not too much shorter or
else the printer fills up its buffer too fast. This function is not
applicable for C/T hotport.
97