8-BIT ISA BUS DUAL COM + PARALLEL LPT Vintage 8-Bit ISA Dual Serial & Parallel I/O Controller

CONTROLLER: GOLDSTAR GM16C452PL | FCC ID: EUD 5U9 BRI4193 | DUAL BRACKET SET

Bus Interface 8-Bit ISA (XT / AT) Serial Ports 2x RS-232 (9-Pin + 25-Pin) Parallel Port 1x Bi-Directional LPT (DB-25) Hardware Controller GoldStar GM16C452PL Hardware Architecture & Retro Computing Utility

Manufactured in late 1991, this dual serial and parallel controller is powered by the GoldStar GM16C452PL multifunction I/O chip. Integrating two independent 16C450-compatible UART serial channels and a full Centronics-compatible parallel printer port on a single silicon package, it delivers rock-solid input/output connectivity for vintage PC builds.

Because it utilizes an 8-bit ISA bus interface, it is universally compatible with everything from original 8088/8086 IBM PC/XT compatibles up through 286, 386, 486, and early Pentium systems. Complete with its original secondary slot bracket and ribbon cable, this card provides simultaneous hookup for serial mice, external modems, serial file transfers (LapLink/InterLink), and parallel printers or ZIP drives without fighting onboard resource conflicts.

Bench Diagnostics & Quality Verification

• PASS 8-Bit ISA Bus Enumeration: Tested clean across standard ISA slots with stable bus timing and zero address decode errors.
• PASS Primary Serial Port (COM A): Bracket-mounted 9-pin DE-9 male serial port tested and verified with standard serial mouse input under DOS.
• PASS Secondary Serial Port (COM B): Ribbon-cable expansion 25-pin DB-25 male serial port tested clean with external serial communication.
• PASS Parallel Port (LPT): 25-pin DB-25 female printer port tested with verified handshaking and clean print spool data transfer.
• PASS Jumper & Logic Integrity: 18.432 MHz crystal oscillator, Motorola MC1488/MC1489 drivers, and blue IRQ/COM selector jumpers verified in full working order.

Hardware Specifications Card Type Dual Serial (RS-232) & Parallel (Centronics/Bi-directional) I/O Card Primary Chipset GoldStar GM16C452PL (Dual 16C450 UARTs + Parallel Controller) FCC ID EUD 5U9 BRI4193 PCB Silkscreen / Part Number 42-91-009 / PC-P-90-94V0 Bus Interface 8-Bit ISA (Compatible with 8-bit XT and 16-bit AT ISA slots) Serial Ports 1x DE-9 Male (COM A) on main card + 1x DB-25 Male (COM B) on 2nd bracket Parallel Port 1x DB-25 Female (LPT1 / LPT2 selectable) Baud Rate Generator 18.432 MHz Crystal Oscillator (EA 18.432) Line Drivers / Receivers Motorola MC1488M / MC1489AD / STMicroelectronics 74LS245D Address / IRQ Selectors Hardware Jumpers for COM1–COM4 (IRQ3, IRQ4) & LPT1–LPT2 (IRQ5, IRQ7) Form Factor Standard Profile (Main Full-Height Bracket + Secondary Expansion Bracket) OS Compatibility MS-DOS, PC-DOS, FreeDOS, Windows 3.1x, Windows 95 / 98, OS/2, Linux Era / Date Code Circa Week 43, 1991 (Late 1991 / 1992 Distribution Tag) Logistical Respect™ Dispatch Protocol

1. ESD Shielding: Board and secondary bracket assembly are enclosed together inside a dedicated static-dissipative anti-static bag.
2. Suspension Cocoon: Wrapped in multiple thick layers of heavy-gauge bubble wrap isolating pin headers, ribbon cable, and brackets from shock.
3. Crush-Resistant Shell: Suspended inside a rigid corrugated shipping box with perimeter impact clearance.
4. Builder's Paper Overwrap: Entire shipping box is tightly wrapped in heavy-duty builder's kraft paper for an additional layer of moisture and abrasion protection.
5. Fast Carrier Induction: Dispatched promptly with full commercial tracking uploaded immediately upon drop-off.

Package Contents

• 1x Vintage 8-Bit ISA GoldStar GM16C452PL Serial & Parallel I/O Card
• 1x Matching Secondary Expansion Bracket with DB-25 Serial Port & Ribbon Cable
• 1x Personalized handwritten thank-you note from fellow retro tech enthusiasts

Plug-and-play BIOS support: Recognized natively by all standard PC/XT/AT BIOS implementations without requiring software drivers.