Serial interface, Input connector, Pin configuration – Seiko FB-900 User Manual

Page 170: Timing chart

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Serial interface

7-5

— 7. Interface specifications —

Serial interface

Pin configuration

Input connector (25-pin serial connector)

1

3

2

4

5

6

7

8

9

10

11

12

13

15 14

16

17

18

19

20

21

22

23

24

25

PIN

SIGNAL

IN/OUT

PIN

SIGNAL

IN/OUT

1

CHASSIS GND

14

NC

2

TXD

OUT

15

NC

3

RXD

IN

16

NC

4

RTS

OUT

17

NC

5

CTS

IN

18

NC

6

DSR

IN

19

NC

7

SIGNAL GND

20

DTR

OUT

8

CD

IN

21

NC

9

NC

22

NC

10

NC

23

NC

11

SRTS

OUT

24

NC

12

NC

25

NC

13

NC

To printer

INPUT

330pF

(75189 or equivalent)

To printer

OUTPUT

(75188 or equivalent)

Signal levels
OFF: Indicates "MARK" at a level from -3 to -15 V.
ON: Indicates "SPACE" at a level from +3 to +15 V.

Input signal

Output signal

Input/output conditions

(1) NC means "not connected".
(2) The CHASSIS GND and SIGNAL GND are connected inside

the printer.

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