I'm not sure why, but my post that carlfogel refers to above no longer has a working link to the Star printer config. So here is what works for me:
Installing the Star Micronics TSP800 Printer (network)
Configuring the ethernet interface and printer port (Windows 7)
1. Open Devices and Printers from the Start Menu, and click on ?Add a printer?
2. Select ?Add a local printer?
3. Choose ?Create a new port?
4. Choose ?Standard TCP/IP port? from the drop down menu
5. Enter the printer's network IP address (ie: 192.168.2.9) under Host name or IP Address
6. Enter Star TSP800 under Port Name
7. Wait while Windows detects the port; it may take a few minutes
8. In the ?Additional Port Information? window that opens, choose ?Generic Network Card?
9. When asked to choose the printer driver, select ?Star? and then ?TSP800 (TSP847)? from the list. (If the printer is not list, install the printer driver from the printer's CD, or download the driver installation program from:
http://www.starmicronics.com/supports/starlegacydrivers.aspx#TSP800 )
10. After the printer is installed, it should appear in the Devices & Printers? window
After the TSP800 is installed, configure the settings for prescription printing:
1. Open Devices and Printers from the Start Menu, right click on the TSP800 and choose ?Printer Properties?. You must set up 3 areas in ?Printer Properties? for correct Rx printing and paper cutoff
2. Click on the "General" tab at the top left, then the "Preferences" button at the bottom.
3. In the window that opens, click the "Paper Quality" tab at the top, and then the "Advanced" button on the lower right. Under "Paper Size", choose 104 x 200 mm.
4. Click "OK" to close the window, then "Apply" in the next window, and then "Okay" to close the window. You should be back at the "Properties" window again.
5. Click the "Advanced" tab at the top of the "Properties" window, and then "Printing Defaults" at the lower left.
6. Click "Paper Quality" tab at the top, and then the "Advanced" button on the lower right.
7. Under "Paper Size", choose 104 x 200 mm.
8. Click "OK" to close the window, then "Apply" in the next window, and then "Okay" to close the window. You should be back at the "Properties" window again.
9. Click the "Device Settings" tab at the top of the "Properties" window.
10. Change the follow settings:

-- "Form to Tray Assignment: FRICTION:" ----> 104 x 120mm

-- "Paper Type" ----> "Black Mark".

-- "Black Mark Detect on Power On" ----> "Enable".

-- "Page Cut Type" ----> "Full Cut"

-- "Document Cut Type" ----> "Full Cut"
11. Click "Apply" then "Okay" to close the "Properties" window.
12. Power cycle the TSP800 by turning it off and then on. The status light should turn green, and the printer should advance the paper roll to the first black timing mark, and cut it off.
Also, remember that you must choose the printing profile for the TSP800 in the "Set Prescription Format" area under "Administrator Options" in Amazing Charts.
