Epson Stylus Color 400 Service Manual download pdf (Page 25)

Chapter1 Product Description

Rev. A

1-1

[Signal level: TTL compatible (IEEE-1284 level 1 device)]

Parameter Minimum Maximum Condition

VOH* --- 5.5V

VOL* -0.5V ---

IOH* --- 0.32mA VOH = 2.4V

IOL --- 12mA VOL = 0.4V

CO --- 50pF

VIH --- 2.0V

VIL 0.8V ---

IIH --- 0.32mA VIH = 2.0V

IIL --- 12mA VIL = 0.8V

CI --- 50pF

*A low logic level on the Logic H signal is 2.0V or less when the printer is powered off and this

signal is equal or exceeding 3.0V when the printer is powered on. The receiver shall provide an

impedance equivalent to 7.5K ohm to ground.

[Data Transmission Timing for Reverse Channel]

The figure below shows timing chart of Parallel Interface Reverse channel.

1.3.3 Prevention Hosts from Data Transfer time-out

Generally, hosts abandon data transfer to peripherals when a peripheral is in the busy state

for dozens of seconds continuously. To prevent hosts this kind of time-out, the printer receives

data very slowly, several bytes per minute, even if the printer is in busy state. This showdown

is started when the rest of the input buffer becomes several hundreds of bytes. Finally, the printer is

in the busy state continuously when the input buffer is full.

Table 1-14. Signal Level

Virtual Busy Status

Figure 1-9. Parallel Interface Timing Chart(Reverse Channel)

1 2 ... 20 21 22 23 24 25 26 27 28 29 30 ... 144 145

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Epson Stylus Color 400 Service Manual Page 25