With the status flag set and data reception prohibited, the vacant area of the buffer gradually increases as the printer continues to print. When the vacant area for bytes reaches the preset recovery value (see Table 12), the flag is reset and data entry is again enabled.

Buffer Operation Disabled

Under this condition, the flag is output from the DTR (pin No. 20) in the case of RS-232D, from the TRA and TRB (pin No. 11, 13) in the case of RS-422A, and from the TTY-TXD (pin No. 17) in the case of Current Loop.

When DIP switch 3-l is ON (buffer is disabled), flag set timing is set to 16 bytes and flag reset timing is set to 32 bytes.

Table 12. Flag set/reset conditions

 

 

DTR Handshaking

X-on/X-off handshaking

 

 

 

 

 

Flag

is set

RS-232D: negative EIA

Transmitting

X-off

(not

ready to

level

character

 

accept data)

RS-422A: negative EIA

 

 

 

 

level

 

 

 

 

TRA-TRB,

 

 

 

 

TRA: inverted

 

 

 

 

TRB: noninverted

 

 

 

 

20-mA Current Loop: low

 

 

 

 

impedance (Current on)

 

 

 

 

 

 

Flag is reset

RS-232D: positive EIA

Transmitting

X-on

(ready to

level

character

 

accept data)

RS-422A: positive EIA

 

 

 

 

level

 

 

 

 

TRA-TRB

 

 

 

 

TRA: inverted

 

 

 

 

TRB: noninverted

 

 

 

 

20-mA Current Loop: high

 

 

 

 

impedance (Current off)

 

 

 

 

 

 

 

19