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Parallel Pinout Diagrams

 
IEEE1284 Pinouts

General
The IEEE 1284 standard was approved in march 1994 as the Standard Signaling Method for a Bidirectional Parallel Peripheral Interface for Personal Computers. And is the first approved standard for parallel transmission on PCs. The idea was to create a standard that was backward compatible with the old Centronics standard. With the new standard higher speeds and greater distances are possible plus there is the capability also sending to the host (bidirectional).

The maximum speed that is allow over the new parallel bus is 2 MBps (16 Mbps). The cable length is determend by the mode that is used. Within the IEEE 1284 there are 5 different modes defined:

Compatibility mode
This one is compatible with all previous version of the parallel port. Data rates are possible up to 150 bytes per second @ 6 meter (20 ft) with an AB-cable or up to 150 kbps @ 10 meter (32.8 ft) with a CC-cable.

Nibble mode
This is a uni-directional interface. Only data transfers from periperal to host are possible. Data is send from the e.g. printer to the PC in a nibbles (4 bits). Combined with the Compatibility mode this is what Hewlett Packard calls "Bi-tronics".
For the Nibble-mode speeds of up to 50 kbps @ 6 meter (20 t) are possible. With a CC-cable this can be increased to up to 150 kbps @ 10 meter (32.6 ft).

Byte mode
Byte mode makes it possible to send data from the peripheral to the host in bytes (8 bits). Combined with the Compatibility mode you have a "Bidirectional port".
Speeds are possible up to 500 kbps @ 10 meter (32.8 ft) when CC-cables are used.

EPP mode
This is a mode in which data can be transfered from host to peripheral or vice versa, but not at the same time, so this is a half-duplex connection (mostly used by CD-ROMs, tape-drives, harddisks).
Speeds can range from 500 kbps to up to 2 Mbps @ 6 meter (20 ft) or 10 meter (32.8 ft) when CC-cables are used.

ECP mode
This is a mode in which data can be transfered from host to peripheral or vice versa, but not at the same time, so this is a half-duplex connection (mostly used by printers and scanners).
Speeds can range from 500 kbps to up to 1 Mbps @ 6 meter (20 ft) or 10 meter (32.8 ft) when CC-cables are used.

Every device can only be in one mode at a time. So the IEEE 1284 workgroup invented a way of determining which mode should be used with which device, that is called Negotiation. The Negotiation part doesn't affect older devices, but IEEE 1284 compliant devices can tell the host what they are and which mode to use.

Cables and Connectors
The IEEE defined three types of connectors and six types of cables. The type A connector is the parallel port connector (Sub-D25) found on most computers. The type B connector is what is usually called the Centronics connector. And there is a new connector that is called MDR36 and which is called type C. The pinning for the Centronics and Sub-D25 is not changed.
The different cables that are defined are:

AMAM

Type A male to type A male

AMAF

Type A male to type A female

AB

Type A male to type B

AC

Type A male to type C

BC

Type B male to type C

CC

Type C male to type C

 

Also the cable characteristics are defined:

  • The cable shield must be connected to the connector back shell using a 360 concentric method
  • The shield must be minimal 85 % optical braid coverage over foil
  • The maximum crosstalk is not greater then 10 %
  • All signals are send over a twisted pair with their signal ground return
  • Each pair must have an impedance of 62 6 ohms @ 4 to 16 MHz

Pinning Sub-D25 A-connector

 

Male

Female

Pin

Signal

Abbr.

Source

1

Data Strobe (low)

STROBE

Computer

2

Data Bit 1 (LSB)

D1

Computer

3

Data Bit 2

D2

Computer

4

Data Bit 3

D3

Computer

5

Data Bit 4

D4

Computer

6

Data Bit 5

D5

Computer

7

Data Bit 6

D6

Computer

8

Data Bit 7

D7

Computer

9

Data Bit 8 (LSB)

D8

Computer

10

Acknowledge (low)

ACK

Printer

11

Busy (high)

BUSY

Printer

12

Paper End (high)

PE

Printer

13

Select (high)

SEL

Printer

14

Auto Line Feed (low)

LF

Computer

15

Error (low)

ERROR

Printer

16

Initialize Printer (prime-low)

PRIME

Computer

17

Select Input (low)

SEL

Computer

18

Return/ground

GND

-

19

Return/ground

GND

-

20

Return/ground

GND

-

21

Return/ground

GND

-

22

Return/ground

GND

-

23

Return/ground

GND

-

24

Return/ground

GND

-

25

Return/ground

GND

-

 

Pinning 36 pin Amphenol B-connector
 

 

Male

Female

Pin

Signal

Abbr.

Source

1

Data Strobe (low)

STROBE

Computer

2

Data Bit 1 (LSB)

D1

Computer

3

Data Bit 2

D2

Computer

4

Data Bit 3

D3

Computer

5

Data Bit 4

D4

Computer

6

Data Bit 5

D5

Computer

7

Data Bit 6

D6

Computer

8

Data Bit 7

D7

Computer

9

Data Bit 8 (LSB)

D8

Computer

10

Acknowledge (low)

ACK

Printer

11

Busy (high)

BUSY

Printer

12

Paper End (high)

PE

Printer

13

Select (high)

SEL

Printer

14

Supply Ground

-

15

Oscillator Transmit

Printer

16

Logical Ground

-

17

Chassis Ground

-

18

+5 Vdc

+V

Printer

19

Return Data Strobe

-

20

Return Data Bit 1

-

21

Return Data Bit 2

-

22

Return Data Bit 3

-

23

Return Data Bit 4

-

24

Return Data Bit 5

-

25

Return Data Bit 6

-

26

Return Data Bit 7

-

27

Return Data Bit 8

-

28

Return ACK

-

29

Return BUSY

-

30

Return Input Prime

-

31

Input Prime (low)

Computer

32

Fault (low)

FAULT

Printer

33

-

-

-

34

-

-

-

35

-

-

-

36

-

-

-

 

Pinning MDR 36 pins C-connector
 

Male

Female

Pin

Signal

Abbr.

Source

1

Busy (high)

BUSY

Printer

2

Select (active high)

SEL

Printer

3

Acknowledge (active low)

ACK

Printer

4

Error (Fault- active low)

ERROR

Printer

5

Paper Error (active high

PE

Printer

6

Data Bit 0 (LSB)

D0

Computer

7

Data Bit 1

D1

Computer/Printer

8

Data Bit 2

D2

Computer/Printer

9

Data Bit 3

D3

Computer/Printer

10

Data Bit 4

D4

Computer/Printer

11

Data Bit 5

D5

Computer/Printer

12

Data Bit 6

D6

Computer/Printer

13

Data Bit 7 (MSB)

D7

Computer/Printer

14

Initial

INIT

15

Data Strobe (low)

STROBE

Computer

16

Select Input (active low)

SI

17

Auto Line Feed (active low)

ALF

18

Host Logic High

HLH

Computer

19

Return/Ground

RGND

20

Return/Ground

RGND

21

Return/Ground

RGND

22

Return/Ground

RGND

23

Return/Ground

RGND

24

Return/Ground

RGND

25

Return/Ground

RGND

26

Return/Ground

RGND

27

Return/Ground

RGND

28

Return/Ground

RGND

29

Return/Ground

RGND

30

Return/Ground

RGND

31

Return/Ground

RGND

32

Return/Ground

RGND

33

Return/Ground

RGND

34

Return/Ground

RGND

35

Return/Ground

RGND

36

Peripheral Logic High

PLH

Printer

 

Functional Description

STROBE

Active low pulse used to transfer data into the printer.

Pulse with must be between 0.5 and 500 microseconds for most printers.

ACK

Active low pulse indicates that data has been received and the printer is ready to accept more.

BUSY

A high signal indicates that the printer cannot receive data.

PE

A high signal indicates that the printer is out of paper (Paper End)

SELECT OUT

A high signal indicates that the printer is on-line

AUTO FEED

A low signal indicates to the printer that a line feed is required after each Carriage return.

This signal is used as a ground line by some manufacturers.

OSCXT

A 100-200 KHz signal used by true Centronics printers only.

+5V

+5Vdc

Not provided by all manufacturers

PRIME

A low signal resets the printer to its power-up state and the printer buffer is cleared

FAULT

A low signal indicates that the printer is in an off-line or error state

LINE COUNT

Used by true Centronics printers only.

Most of the time not used

LINE COUNT

See 34

SELECT IN

A high signal indicates to the printer that a DC1/ DC3 code is valid.

This signal is used by a few manufacturers

Host Logic High

A high signal indicates that the host is alive (turned on).

Specific IEEE 1284 signal.

Peripheral Logic High

A high signal indicates that the peripheral (printer) is alive (turned on).

Specific IEEE 1284 signal.