IEEE1284-C Parallel

36 pin MDR36 female connector.

36 pin MDR36 male connector.

The IEEE 1284-C connector is a 36-pin mini-Centronics MDR (Micro D Ribbon) interface defined in IEEE 1284-1994 and revised in IEEE 1284-2000 for bidirectional parallel communications between personal computers and peripherals. Operating at 0.050-inch pitch — half that of the traditional 1284-B Centronics connector — it was introduced to allow a more compact form factor suitable for laptop docking stations and some HP LaserJet and DeskJet printers. Unlike the 1284-A (DB-25) and 1284-B (36-pin Centronics) connectors, the 1284-C type can serve on both the host and peripheral ends of a cable. It carries the same 17 signal lines as the other IEEE 1284 connector types, but adds two IEEE 1284-specific signals: Host Logic High (pin 18) and Peripheral Logic High (pin 36), which are absent from the 1284-A and 1284-B connectors.

Notes

• The connector uses 0.050-inch pitch, versus 0.085-inch for the 1284-B Centronics connector, making it mechanically incompatible with standard Centronics cables.
• The 1284-C type may be used on either or both ends of a cable, enabling host-to-host or host-to-peripheral configurations.
• Pin 18 (Host Logic High) and pin 36 (Peripheral Logic High) are IEEE 1284-specific signals; they supply a logic-high reference and are not present on 1284-A or 1284-B connectors.
• Pins 19–35 are all signal return (ground) lines.
• Maximum cable length per IEEE 1284 is 25 feet; cable characteristic impedance is 62 ± 6 ohms.
• All five IEEE 1284 transfer modes (Compatibility, Nibble, Byte, EPP, ECP) are supported over this connector.

Signals

• BUSY — Peripheral busy; asserted high by the printer when unable to accept data.
• SEL — Select; indicates the peripheral is on-line and selected, asserted high.
• ACK — Acknowledge; low pulse from peripheral confirming receipt of a data byte.
• ERROR — Error / Fault; asserted low by peripheral to signal an error condition.
• PE — Paper Error; asserted high by printer when paper is out or a paper fault occurs.
• D0–D7 — Bidirectional 8-bit data bus (D0 LSB, D7 MSB); direction depends on the active transfer mode.
• INIT — Initialise; host-driven signal used to reset the peripheral.
• STROBE — Data Strobe; asserted low by host to clock data into the peripheral during Compatibility mode writes.
• SI — Select Input; asserted low by host to select the peripheral.
• ALF — Auto Line Feed; asserted low by host to instruct the printer to perform an automatic line feed after each carriage return.
• HLH — Host Logic High; IEEE 1284-specific pin providing a logic-high reference from the host (pin 18, unique to 1284-C).
• RGND — Return / Ground; signal return lines (pins 19–35).
• PLH — Peripheral Logic High; IEEE 1284-specific pin providing a logic-high reference from the peripheral (pin 36, unique to 1284-C).

References

• IEEE 1284-2000 — IEEE Standard Signaling Method for a Bidirectional Parallel Peripheral Interface for Personal Computers
• IEEE 1284-1994 — IEEE Standard Signaling Method for a Bidirectional Parallel Peripheral Interface for Personal Computers (superseded)
• IEEE 1284-1994 Standard (Parallel Port) — MCABase Technical Reference

Category:Parallel Connectors