Epson SQ-2550 User Manual page 187

Interface Boards
Baud rate selection
You can select from the following baud rates: 300, 600, 1200,
2400, 4800, 9600, or 19200 bits per second (BPS). When setting
the baud rate, make sure you use the bit rate selection table
below.
Handshaking timing
When the vacant area for data in the input buffer drops to 256
bytes, the printer outputs an X-off code or sets the DTR flag to
"1" (MARK) indicating that it cannot receive data.
Once the vacant area for data in the buffer recovers to 512
bytes, the printer outputs an X-on code or set the DTR flag to
"0" (SPACE) indicating that it is again ready to receive data.
Error handling
When a parity error is detected, your printer prints an asterisk
(*). All other errors, including framing and overrun, are
ingnored.
5-40 Using Printer Options