PCI-6503 | Product Overview

The NI PCI-6503 is a low-cost 24-channel TTL/CMOS digital I/O card (non-isolated, 82C55 PPI, 50-pin connector) for PCI bus, half-length card. It features:

24 bidirectional DIO (5 V TTL/CMOS, 2.4 mA) + programmable power-on state + 2-wire handshake + interrupt capability

Suitable for general digital quantity control, relay drive, switch quantity acquisition, peripheral handshake, TTL level device interconnection, and low-cost 24-channel DIO system.

Part number: 777690-01 / 185183-01; discontinued (EOL), replacement model PCIe-6509.

I. Basic Information

Model: PCI‑6503

Brand: National Instruments (NI)

Series: 650x Low-cost Parallel DIO Series

Bus: PCI (5 V compatible, half-length card)

Connector: 1 × 50-pin female connector (D‑Sub)

Chip: 1 × 82C55A PPI (Programmable Peripheral Interface)

Driver: NI‑DAQmx / Traditional NI‑DAQ

Operating Temperature: 0 ~ 55 °C

Isolation: No isolation (non-isolated type)

Features: 24 channels, 3 8-bit ports, ports can be configured for input/output, power-on state can be jumper-selected, supports handshake and interrupts

II. Digital I/O (DIO, 24 channels)

Channels: 24 bidirectional TTL/CMOS, divided into 3 8-bit ports (A/B/C)

Level: 5 V TTL/CMOS (high ≥ 2.0 V, low ≤ 0.8 V)

Drive Capacity: 2.4 mA per channel (sourcing / sinking current) NI

Port Configuration:

Port A, B: General input/output

Port C: Can be used as I/O or handshake/control signal

Power-on State: Can be jumper-set to full high or full low (each line 100 kΩ pull-up / pull-down)

Maximum Rate: Approximately 1 MHz (software-dependent)

Function: Unidirectional / Bidirectional, 2-wire handshake, interrupt request, event trigger NI

III. Trigger and Interrupt

Interrupt: Supports PPI interrupt (maskable)

Handshake: 2-wire hardware handshake (STB/IBF, etc.)

Data Transfer: Query, interrupt, programmable I/O

IV. Physical and Environmental

Size: Half-length PCI, approximately 12.4 cm × 12.6 cm × 2.2 cm

Weight: Approximately 0.1 kg

Temperature: 0 ~ 55 °C (operating), -20 ~ 70 °C (storage)

Humidity: 10% ~ 90%, no condensation

V. Installation and Usage Tips Installation

Power off and disconnect, insert into the standard PCI half-length slot; after startup, identify in MAX, install NI-DAQmx.

Wiring (50-pin D-Sub)

DIO lines: directly connect to 5 V TTL devices, common ground; no isolation, avoid ground loops and high voltage.

Port C: used for handshakes (such as STB, IBF, ACK) or status signals.

Power-on jumper: the card's jumper selects default high/low to avoid incorrect operation upon power-on.

Software configuration (NI-DAQmx)

Port mode: A/B set as input or output, C set as I/O or handshake

Interrupts: enable PPI interrupts for event response

Handshakes: enable 2-wire handshakes, suitable for printers / peripherals Notes for Attention

No isolation, not suitable for industrial strong interference / high voltage scenarios.

Each current path does not exceed 2.4 mA, to avoid overload.

Long-distance transmission requires buffering / driving to reduce interference.

Six, Core Features

24 channels of 5 V TTL/CMOS DIO (3×8-bit ports, 2.4 mA) + handshake + interrupt + programmable power-on state

PCI half-length card, 50-pin D-Sub, 82C55 PPI, NI-DAQmx driver

Low cost, easy integration, suitable for general switch quantity control and acquisition

Applicable: relay control, indicator light driving, switch quantity input, TTL peripheral interconnection, laboratory / desktop automation, low-cost 24-channel DIO system