The T10 and T11 use a variant of the raster protocol. When the printer is in "Service Required" mode (flashing ink and paper lights simultaneously), it rejects standard print commands. However, it remains listening on USB for specific Reverse Engineering Transfer (RRT) commands.
Have a different error code? If your lights are flashing alternately (one then the other), that is a paper feed jam. If they are flashing together (sync), that is the waste ink counter. Reset wisely. Epson Stylus T10 T11 Working Resetter
Using an solves the software counter problem, but it does not solve the physical problem. If you reset the counter, you are essentially telling the printer that the waste ink pad is brand new. If the pad is actually full of ink, resetting the counter will cause ink to overflow. The T10 and T11 use a variant of the raster protocol
"Service required," the screen read. "Parts inside your printer are at the end of their service life." Have a different error code
Epson programmed a inside the printer’s EEPROM. When that counter hits a specific number (usually around 15,000 to 20,000 pages or 50 power cleanings), the printer hard-locks itself.
Your T10/T11 will now run a massive 3-minute ink charging cycle. Let it finish. It will sound terrible. That is normal.