Citizen PROjet II  (260-2957)         Pinouts          Faxback Doc. # 14711

Parallel Interface Pinouts

The parallel interface cable must be a standard shielded, twisted pair
cable, with the connector and shield connected.

Compatibility:                          CENTRONICS
Circuit logics:                         TTL
Data format:                            8 bits
Logic voltage levels:                   TTL-compatible
Connector:                              Amphenol 36 pins (female)

The following diagram illustrates the pins and corresponding signals on
the parallel interface connector.

STROBE 01 >                   19 GROUND
DATA 0 02 >                   20 GROUND
DATA 1 03 >                   21 GROUND
DATA 2 04 >                   22 GROUND
DATA 3 05 >                   23 GROUND
DATA 4 06 >                   24 GROUND
DATA 5 07 >                   25 GROUND
DATA 6 08 >                   26 GROUND
DATA 7 09 >                   27 GROUND
ACKNOWLEDGE 10 <              28 GROUND
BUSY 11 <                     29 GROUND
PAPER EMPTY 12 <              30 GROUND
NC 13 <                       31 INIT.
NC 14 >                       32 ERROR
NC 15 -                       33 LOGIC GROUND
LOGIC GROUND 16               34 NC
FRAME GROUND 17 -             35 +5 v (PULL-UP, 3.3K ohm)
+5 v (PULL-UP, 3.3k ohm) 18<  36 nc
Connecor Pins and Corresponding Signals

The following table contains the signals exchanged by the printer and
computer, and their meanings.

PIN         SIGNAL                             SIGNAL DESCRIPTION
            DIRECTION

1           to printer                    STROBE

                                          Signal valid at logic level 0,
                                          used to transfer data to the
                                          printer.

                                          Pulse duration must be at least
                                          0.5micros.

2-9         to printer                    DATA 0-7

                                          These 8 lines carry the data
                                          transmitted to the printer.

                                          Signal duration must be stable
                                          at least 0.5micros before the
                                          falling edge of STROBE signal,
                                          and remain stable at least
                                          0.5micros after its rising
                                          edge.

Data 7 is the most significant bit but is not used in 7-bit ASCII mode.

10          from printer                  ACK

                                          Normally at 1; set at 0 to
                                          indicate that the printer has
                                          accepted the single character
                                          transmitted.

11          from printer                  BUSY

                                          Normally at 0; logic level 1
                                          indicates that the printer
                                          cannot accept any characters,
                                          and is activated in the
                                          following cases: during data
                                          transfer, buffer full, error
                                          condition.

12          from printer                  PAPER EMPTY

                                          Normally at 0; set at 1 if there
                                          is no paper.

                                          This signal is asynchronous with
                                          respect to Strobe, Busy and
                                          ACK.

13          from printer                  ON LINE

                                          Not used.

14          to printer                    AUTOFEED XT

                                          Not used.

16            ---                         LOGIC GROUND

                                          Logic ground level (0 V).

17            ---                         FRAME GROUND

                                          (Printer earthed through host).

18          from printer                  +5 V (PULL-UP)

                                          Supplied across a 3.3 Kohm
                                          resistor.

19-30         ---                         SIGNAL GROUND

                                          Twisted pair return lines.

31          to printer                    INIT.

                                          A level 0 pulse of width greater
                                          than 10micros (sent by host)
                                          resets the printer and clears
                                          the print buffer.

32          from printer                  ERROR

                                          Normally at 1; set at 0 for
                                          anomalies such as paper out,
                                          printer off line, printer fault
                                          condition.

33            ---                         LOGIC GROUND

                                          Logic ground level (0 V).

35          from printer                  +5 (PULL-UP)

                                          Supplied across a 3.3 Kohm
                                          resistor.

36          to printer                    SELECT-IN

                                          Not used.


(LB/all-04/21/95)