Epson LQ-2550 User Manual - Page 247

Printing enabled/disabled signals and control conditions, Technical Specifications

Page 247 highlights

l All interface conditions are based on TTL level. Both the rise and the fall times of each signal must be less than 0.2 microseconds. l Data transfer must be carried out by observing the ACKNLG or BUSY signal. Data transfer to this printer can be carried out only after receipt of the ACKNLG signal or when the level of the BUSY signal is LOW. Printing enabled/disabled signals and control conditions The following table shows the relationship between printing being enabled or disabled, the on line/off line status, and the receipt of the data on/off control characters, DC1 or DC3. ON LINE SLCT IN DClIDC3 ERROR BUSY tt$icator (Data on/off control) ACKNLG Printing (Disabled/ enabled) on line on line off line High DC1 High Recv'd High DC3 High Recv'd High/Low DC1 /DC3 Low (no effect) (no effect) High/Low Pulsed Enabled ea. char. High/Low Pulsed Disabled' ea. char. High Not Disabled generated *While printing is disabled, character data is being received and acknowledged so that the printer can look for another DC1 character, which would allow it to resume printing. Technical Specifications A-11

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l
All interface conditions are based on TTL level. Both the rise and the
fall times of each signal must be less than 0.2 microseconds.
l
Data transfer must be carried out by observing the ACKNLG or
BUSY signal. Data transfer to this printer can be carried out only
after receipt of the ACKNLG signal or when the level of the BUSY
signal is LOW.
Printing enabled/disabled signals and control conditions
The following table shows the relationship between printing being
enabled or disabled, the on line/off line status, and the receipt of the data
on/off control characters, DC1 or DC3.
ON LINE SLCT IN
DClIDC3
ERROR BUSY
tt$icator
(Data
on/off
control)
ACKNLG Printing
(Disabled/
enabled)
on line
High
DC1
High
High/Low Pulsed
Enabled
Recv’d
ea. char.
on line
High
DC3
High
High/Low Pulsed
Disabled’
Recv’d
ea. char.
off line
High/Low DC1
/DC3
Low
High
Not
Disabled
(no effect) (no effect)
generated
*While printing is disabled, character data is being received and
acknowledged so that the printer can look for another DC1 character,
which would allow it to resume printing.
Technical Specifications
A-11