If you are getting intermittent communications with a zebra wireless printer try this
Zebra Wireless desktop printers Sleep Mode Turn Off
Open Hyperterminal to the IP address of the printer and port 9100

Click PropertiesClick ASCII Setup

Check off the boxes in Orange Then Click OK and OK again

Copy and paste the first 2 lines below (in BOLD) including the white space 3rd line
Now Go back to hyperterminal and Click Edit then Paste to Host. Then copy the 2nd group of lines and do it again.
! U1 setvar "power.energy_star.enable" "off"
! U1 setvar "power.energy_star.timeout" "0"
! U1 setvar "power.sleep.enable" "off"
! U1 setvar "power.sleep.timeout" "0"