Xerox 4520mp manual Port Polling Without a Hard Disk Installed

The 4520/4520mp printers provide a parallel port, serial port, and three additional network interface port options, all of which may be active at the same time. Automatic switching among all active I/O (input/output) ports is supported.

Port Polling Without a Hard Disk Installed

To coordinate automatic switching among the ports, the printer monitors the parallel, serial, and network interface ports for incoming data. When a print job is detected on one port, the printer sends a busy signal to the other ports and queues the print job into memory for processing. This is called port polling. Note that while all ports may be simultaneously active, only one port at a time is able to receive a print job.

When print jobs are pending on all five ports (parallel, serial, Ethernet, LocalTalk, and Token Ring), the port polling sequence is:

1Parallel

2Serial

3Ethernet

4Token Ring

5Back to Parallel

LocalTalk is not a part of this sequence. When a print job is detected on the LocalTalk port, the print job is put in the queue immediately after any current job finishes.

Note

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