Epson T88III specifications Near end detection

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2.1.2.7 Reception of status from the printer through the bidirectional parallel interface

In the bidirectional parallel interface specifications, the printer status transmission is available by using the both-way communication facility in the Nibble/Byte Modes in accordance with the IEEE 1284.

In this case, different from in the RS-232 serial interface specifications, the real-time interruptions from the printer to the host are disabled and thus precautions must be taken to the followings.

1)Allowable capacity of the printer internal buffer is 99 bytes (except ASB status). The status signals exceeding this capacity will be discarded. To prevent possible loss of status, the host shall be ready for data acception (Reverse Mode).

2)When ASB is used, the host is preferably in the wait state for data acception (Reverse Idle Mode). When this state is not available, the host shall enter the Reverse Mode to always monitor the presence of data.

3)When ASB is used, preference shall be given to the ASB status for transmission over the other status signals. Any accumulated ASB status signals left for transmission from the last to the newest ASB status transmission shall be transmitted together at a time as one ASB status showing the presence of change, followed by the latest ASB status.

Example: In the normal (wait) state, the ASB status is configured as follows.

First Status Second Status Third Status Fourth Status

0001 1000

0000 0000

0000 0000

0000 0000

When a sequence of operations are proceeded, the near end is detected and the printer cover is opened, then the printer cover is closed, the following pieces of data are accumulated.

	First Status	Second Status	Third Status	Fourth Status	Near end detection
①	0001 1000	0000 0000	0000 0011	0000 0000
					The printer cover is opended.
②	0011 1000	0000 0000	0000 0011	0000 0000
					The printer cover is closed.
③	0001 1000	0000 0000	0000 0011	0000 0000

When the ASB status is received following this, a total of eight (8) bytes of ASB will be transmitted as follows.

Accumulated ASB (①+②+③)

Accumulated ASB (①+②+③)

+

The latest ASB (③)

Fourth Status

First Status	Second Status	Third Status	Fourth Status
0011 1000	0000 0000	0000 0011	0000 0000
First Status	Second Status	Third Status	Fourth Status
0001 1000	0000 0000	0000 0011	0000 0000

2.1.2.8Notes on setting DIP switch 2-1 to ON Refer to Section 2.1.1.6.

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