Help is available in the Xerox Online Support Assistant here on Xerox.com. Here is a link to the Phaser 8550 Knowledge Base solution that may help your machine avoid losing connection when awaking from sleep mode.
Just type in a problem description (in your case type "printer not waking up from power save mode") in the text/search field for the knowledge base and you will find two options under the first solution (there is a "Printer is Not Waking Up From or Coming Out of the Power Saver Mode and the Control Panel Buttons Are Not Responding" solution...the knowledge base articles contain step by step instructions for you to try and resolve the problem).
Hopefully one of these two solutions will help to resolve your problem. If not, at the top of the knowledge base window you will find the 800 number for contacting the Xerox Customer Technical Support (800-835-6100)
A family member has a Phaser 8550. It's been working fine for 3 years, however recently we added a switch to the network, so the printer is connected to the rest of the network via a switch instead of directly to the computer. Every night the desktop we use gets turned off and the printer goes into sleep mode. When the computer is turned on the printer can't be found and windows shows a No DNS Response error. In windows control panel, the printer is shown as offline. the only way to get it to connect to the pc is to delete the printer and reinstall it in windows
we also have a laptop which doesn't have this problem. it just works over the network. laptop is wireless.
Auto IP enable is off
Bootp/dhcp is off.