Epson U375 - TM B/W Dot-matrix Printer Technical Manual Download Page 27

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XON/XOFF control
When XON/XOFF control is selected, the XON and XOFF
output timing is as described below. (XON code: 11H;
XOFF code: 13H) Transmit timing differs depending on the
setting of DIP switch 3 on bank 2.

Table 1-8. XON/XOFF Transmit Timing

(

✽

1) XON is not transmitted when the receive buffer is full.

(

✽

2) XOFF is not transmitted when the receive buffer is full.

Notes on setting DIP switch 2-3 to ON
1) The printer mechanism stops but does not become

BUSY in the following cases:
• When an error occurs.
• When the cover is open.
• When the printer stops printing due to a paper-end.
• When paper is fed using the PAPER FEED button.

2) When handshaking with the printer while using this

switch setting, make sure to monitor the printer with the
GS a command and the ASB function.
With this switch setting, the default value of the GS a
command (

n) is 2. This automatically transmits the

printer status, depending on on-line/off-line changes.

3) When using the DLE EOT or DLE ENQ command, make

sure that the receive buffer does not become full.

• Note on using a host that cannot transmit data when the

printer is BUSY:
If an error occurs when the receive buffer is full and the
printer is BUSY, the DLE EOT and DLE ENQ com-
mands cannot be used.

• Notes on using a host that can transmit data when the

printer is BUSY:
If a DLE EOT or DLE ENQ command is used while
sending bit-image data, and the receive buffer-full state
is encountered during transmission of the data, the

DLE

EOT or DLE ENQ is processed as bit-image data.
In addition, the data transmitted during the receive
buffer-full state may be lost.

Example of use:

Set the receive buffer to 4K bytes, and check the status
with ESC v or ESC u for each line of printing transmit-
ted. Make sure that the data for printing each line does
not cause the printer to enter the receive buffer-full
state.

On-line/off-line switching
This printer has no on-line/off-line switch. It automatically
goes off-line in the following cases:

• The period from power-on (or initialization of the mecha-

nism due to resetting through the interface) until the
printer is ready to receive data.

• During the self-test.
• When the printer cover is open.
• During paper feeding using the PAPER FEED button.
• When the printer stops due to a paper-end (if enabled by

ESC c 4).

• When an error has occurred.

Example serial interface connection
The following illustrates an example serial interface
connection:

Figure 1-17. Serial Interface Connection Example

XON
transmis-
sion

XOFF
trans-
mission

Printer Status

When the printer goes on-
line after power-on or after
resetting with the interface.

When the receive buffer is
released from the buffer-
full state.

When the printer status
changes to on-line. (

✽

When the printer recovers
from an error by using DLE
ENQ 1 or DLE ENQ 2.