36-pin Centronic Connector
The Original IBM PC Parallel Port Pin-Out [also known now as the 'A'
connector], was replaced by IEEE-1284 cable [25 Pin D-Sub on the Host
side].
The IEEE-1284 'A' cable is backwards compatible with the original IBM
Personal Computer [PC] Parallel Port cable and has the same pinout.
The IEEE-1284-B connector is designed to replace the Centronics
pinout
The IEEE 1284-B: connector is a Female 36 pin ribbon connector (.0850
center line) Centronics, Bale locks [Peripheral connector, Printer
side].
The IEEE-1284 'B' cable pin-out or signal assignments are shown below, along with the connector pin locations.
| Pin Number | Signal name | Pin Description and Function |
|---|---|---|
| 1 | nStrobe | Strobe |
| 2 | data0 | Address, Data Bit 0 |
| 3 | data1 | Address, Data Bit 1 |
| 4 | data2 | Address, Data Bit 2 |
| 5 | data3 | Address, Data Bit 3 |
| 6 | data4 | Address, Data Bit 4 |
| 7 | data5 | Address, Data Bit 5 |
| 8 | data6 | Address, Data Bit 6 |
| 9 | data7 | Address, Data Bit 7 |
| 10 | /nAck | Acknowledge |
| 11 | Busy | Busy |
| 12 | PError | Paper End |
| 13 | Select | Select |
| 14 | /nAutoFd | Autofeed |
| 15 | GND | Signal Ground |
| 16 | GND | Logic Ground |
| 17 | GND | Chassis Ground |
| 18 | PLH | Peripheral Logic High |
| 19 | GND | Signal pin 1 GND |
| 20 | GND | Signal pin 2 GND |
| 21 | GND | Signal pin 3 GND |
| 22 | GND | Signal pin 4 GND |
| 23 | GND | Signal pin 5 GND |
| 24 | GND | Signal pin 6 GND |
| 25 | GND | Signal pin 7 GND |
| 26 | GND | Signal pin 8 GND |
| 27 | GND | Signal pin 9 GND |
| 28 | GND | Signal pins 10, 12, 13 GND |
| 29 | GND | Signal pin 11, 32 GND |
| 30 | GND | Signal pins 14, 31, 36 GND |
| 31 | /nInit | Initialize |
| 32 | /nFault | Error |
| 33 | GND | Signal Ground |
| 34 | GND | Signal Ground |
| 35 | GND | Signal Ground |
| 36 | /nSelectIn | Select In |
Personal Computer [PC] Parallel printer bus specification defines a
Point-To-Point asynchronous bi-directional interface. Devices may be
either 1284 compatible {the older parallel port devices} or 1284
compliant. The maximum recommended length for a printer cable is 25 feet.
Centronics parallel cables run out to 12 feet. The IEEE1284 cable
replaced the 'Centronics' cable, the Centronics cable is obsolete.
Operates in five different modes: [The connector or cable does not change
with each different mode, but the function of some of the pins do]
Compatibility mode; Centronics type operation (PC to Peripheral),
providing the original (required) control signaling bits. These bits
include 8 data lines, a Strobe, a Busy, an Acknowledge, a Select, Paper
Empty, Fault, Initialize Printer, Select Printer, and a Auto Feed line.
Compatibility mode is the basic mode of operation, asynchronous, byte
wide operation with a transfer rate of between 50kBps to 150kBps.
Nibble mode; 4 bit data bus (Peripheral to PC), 8 bit data bus (PC
to Peripheral); supporting uni-directional printer interfaces. This
provides an interface which operates full speed forward and half speed in
reverse. The transfer rate is between 50kBps to 150kBps
Byte mode; 8 bit bi-directional bus. Normal port operation. The
transfer rate is between 50kBps to 150kBps
ECP; Extended Capabilities Port. Allowed the PC to send 32 bit
data to the port, than letting the port divide up the data into four 8
byte messages, improving system (PC) operation. Transfer speeds are ten
times faster then the previous modes.
EPP; Enhanced Parallel Port; Allows high-speed transfers of bytes
in either direction. EPP is used with real time controlled peripherals.
EPP transfer times are the same as ECP transfer rates.
| Pin | Compatibility mode | Nibble mode | Byte mode | EPP mode | ECP mode |
| 1 | nStrobe | HostClk | HostClk | nWrite | HostClk |
| 2 | Data 1 | Data 1 | Data 1 | AD1 | Data 1 |
| 3 | Data 2 | Data 2 | Data 2 | AD2 | Data 2 |
| 4 | Data 3 | Data 3 | Data 3 | AD3 | Data 3 |
| 5 | Data 4 | Data 4 | Data 4 | AD4 | Data 4 |
| 6 | Data 5 | Data 5 | Data 5 | AD5 | Data 5 |
| 7 | Data 6 | Data 6 | Data 6 | AD6 | Data 6 |
| 8 | Data 7 | Data 7 | Data 7 | AD7 | Data 7 |
| 9 | Data 8 | Data 8 | Data 8 | AD8 | Data8 |
| 10 | nAck | PtrClk | PtrClk | Intr | PeriphClk |
| 11 | Busy | PtrBusy | PtrBusy | nWait | PeriphAck |
| 12 | PError | AckDataReq | AckDataReq | User defined 1 | nAckReverse |
| 13 | Select | Xflag | Xflag | User defined 3 | Xflag |
| 14 | nAutoFd | HostBusy | HostBusy | nDStrb | HostAck |
| 15 | Signal Ground | - | - | - | - |
| 16 | Logic Ground | ||||
| 17 | Chassis Ground | ||||
| 18 | Peripheral Logic High | ||||
| 19 | (nStrobe)ground return | ||||
| 20 | (Data 1)ground return | ||||
| 21 | (Data 2)ground return | ||||
| 22 | (Data 3)ground return | ||||
| 23 | (Data 4) ground return | ||||
| 24 | (Data 5) ground return | ||||
| 25 | (Data 6) ground return | ||||
| 26 | (Data 7) ground return | ||||
| 27 | (Data 8) ground return | ||||
| 28 | (nACK, PError, Select) ground return | ||||
| 29 | (Busy, nFault) ground return | ||||
| 30 | (nAutoFd, nSelectIn, nInit) ground return | ||||
| 31 | nInit | nInit | nInit | nInit | nReverseRequest |
| 32 | nFault | nDataAvail | nDataAvail | User Defined 2 | nPeriphRequest |
| 33 | Ground | -- | |||
| 34 | Ground | -- | |||
| 35 | Ground | -- | |||
| 36 | nSelectIn | 1284 Active | 1284 Active | nAStrb | 1284 Active |
Back to the main IEEE-1284 bus page.
Parallel Cable Port Pinout ....
Centronics Cable Pin-out ....
1284-A Cable Pinout .... 1284-C Cable Pinout
IEEE1284-A to 1284-B Adaptor
Pinout .. IEEE1284-A to 1284-C Adaptor
Pinout .. IEEE1284-B to 1284-C Adaptor
Pinout
Navigation: Engineering Home > Interface Buses > Cabled Interface Standards > IEEE-1284 Standard > B-Cable Variation.
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