16
Data protocol ❏
DTR/DSR Mode
Set when dip switch #1-6 is ON. Communication is carried out while handshake
is performed with the DTR and DSR signals. Control is executed by selecting
the DTR signal for the busy signal when data is downloaded to the printer data.
“SPACE” indicates the printer can receive data, and oppositely “MARK”
indicates that data cannot be received.
In the ESC/POS mode, control is executed by selecting the DTR signal for the
host computer’s busy signal when data is uploaded from the printer. “SPACE”
indicates the host can receive data, and oppositely “MARK” indicates that data
cannot be received.
If no error occurs for the printer after turning the power on, the DTR signal line
is set to “SPACE.” After the host computer recognizes that the DTR signal line
is “SPACE,” data text is sent to the RXD signal line. When the printer’s
available buffer space drops below the specified number of bytes (256 bytes if
using 4K-byte reception buffer, 16 bytes if using a 45-byte reception buffer; see
3-2 for details), the DTR signal line is set to “MARK.” After the host computer
recognizes that the DTR signal line is “MARK,” data text transmission is
interrupted, but the printer can receive data up until the data buffer becomes full.
Available space in the data buffer increases as printing is executed, and when
the printer’s available buffer space drops below the specified number of bytes
(256 bytes if using 4K-byte reception buffer, 16 bytes if using a 45-byte
reception buffer), the DTR signal line is set to “SPACE.”
In the ESC/POS mode, printer status transmission can be received by the host
in the DTR/DSR communication mode (status is set after the DSR signal is
confirmed as being “SPACE,” with the exception of some status transmission
commands).
RXD
DTR
Data Data Data
Buffer full Buffer empty
Printing
Power ON