Advantech PCL-722 144-Channel Digital I/O ISA Card

The Advantech PCL-722 is a 144-channel digital I/O ISA card engineered for industrial automation, process control, and data acquisition systems. This full-size PC add-on card delivers 144 TTL digital I/O lines organized as six 24-line ports, with each port subdivided into three 8-bit subsidiary ports (A, B, and C). The card emulates 8255 Programmable Peripheral Interface mode 0 functionality with buffered output circuits that exceed standard 8255 driving capacity.

Each 8-bit port can be independently configured via software as input or output, and Port C divides into two 4-bit sections for flexible control schemes.

Technical Specifications

• 144 TTL digital I/O lines in six 24-line ports


• Port organization: Port A and B (8-bit each), Port C (split into two 4-bit ports per channel)


• 8255 PPI mode 0 emulation with buffered output circuits


• Hardware interrupt capability on Port C bits 0 and 3; configurable to IRQ 2, 3, 4, 5, 6, or 7 with tri-stated sharing support


• Output status readback for monitoring digital output levels


• Requires 32 consecutive I/O address locations (base address via 6-position DIP switch); optional 16-location addressing reduces usable I/O to 96 bits


• Power consumption: +5 V @ 1.3 A typical, +5 V @ 1.8 A maximum


• Input logic levels: High 2.0–5.25 V, Low 0.0–0.80 V


• Digital output specifications: Port A/B (Logic 0: 0.4 V max @ 12 mA sink; Logic 1: 2.4 V min @ 8.0 mA source); Port C (Logic 0: 0.5 V max @ 24 mA sink; Logic 1: 2.0 V min @ 15 mA source)


• Form factor: Full-length ISA bus card (334 mm × 100 mm)

Key Features

• Software-configurable input/output on each 8-bit port


• Hardware interrupt generation with multi-board sharing capability


• Direct output readback without intermediate sensing circuitry


• DIP switch-based address configuration throughout IBM PC I/O space

Compatibility & Integration Pin assignments are fully compatible with Opto-22 I/O module racks, enabling straightforward integration into existing industrial control systems. The card fits any full-length ISA-bus expansion slot in IBM PC XT/AT or compatible computers. Six 50-pin male ribbon-cable connectors support field-wiring connections.