Epson 4500 - Manual (Page 188)

The Interface Boards
Baud rate selection
You can select baud rates from 75 to 19,200 BPS (Bits Per Second).
When setting the baud rate, make sure you use the bit rate selection
table for printers with buffers (in the #8143 interface manual).
For more information on the printer’s input buffer settings, see the
section on DIP switch functions in Chapter 3 of this manual.
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.
Error handling
When a parity error is detected, your printer prints an asterisk (*). All
other errors, including framing and overrun, are ignored.
5-50 Using the Printer Options