Memory mode XON/XOFF
The received characters are stored in a FIFO buffer (first in/first out).
The characters are processed in this buffer. The buffer capacity can be
adjusted from 0 to 128 Kb.
If the buffer is full, the interface signals NOT READY (signal acknow-
ledgement: Level 1, -12 V) and XOFF (hex. 13, dec. 19). This results in
stopping the data transmission. When the FIFO buffer is empty again, the
interface signals READY (level 0, +12 V) and XON (hex. 11, dec. 17).
Data transmission can be continued.
In addition, the READY signal is influenced by the status of the printer
(On/Off Line). If the printer assumes an undefined state, the interface
also signals NOT READY and XOFF.
Memory mode Robust
XON/XOFF
Robust XON/XOFF is similar to XON/XOFF. However, the state of the
printer (XON or XOFF) is also periodically transmitted via the TxD line in
the case of Robust XON/XOFF.
Reference manual
Interfaces
186
