Description
IBM 1501485 XM 8-Bit ISA Async Card INS8250N-B RS-232 Serial DB25 Vintage PC
The IBM 1501485 XM is an 8-bit ISA asynchronous serial communications card designed for IBM PC and PC/XT-class systems and compatible ISA bus computers. It provides a single RS-232 serial port via a DB25 bracket connector, enabling the host system to communicate with serial peripherals such as modems, serial printers, plotters, and terminals. The card is built around the National Semiconductor INS8250N-B UART (Universal Asynchronous Receiver/Transmitter), the same core serial controller used in the original IBM PC serial adapter.
Specifications & What's Included
- Part Number: IBM 1501485 XM
- Bus Interface: 8-bit ISA (XT-bus compatible)
- Serial Protocol: RS-232 asynchronous
- UART: National Semiconductor INS8250N-B
- Oscillator: CK1100AC, 1843.200 KHz (TEW, date code /J C86)
- Logic ICs: Texas Instruments SN74LS00N (quad NAND gate) and additional 74-series TTL logic
- External Connector: DB25 female (25-pin D-sub) on bracket
- Number of Serial Ports: 1
- Form Factor: Half-length ISA card with single-slot bracket
- Country of Manufacture: Malaysia (per IC date codes)
- Included: Card only — no cables, driver disks, or documentation
Applications
The IBM 1501485 XM async card dates from the mid-1980s era of 8-bit IBM PC and PC/XT computing, when ISA (then called the PC bus or XT bus) was the dominant expansion standard. Asynchronous serial cards of this type were essential in that period, providing the RS-232 port used to connect modems for dial-up communications, serial dot-matrix and daisy-wheel printers, plotters such as the HP 7470A, and serial terminals. The INS8250 UART was the industry-standard serial controller of the era, and IBM's own asynchronous adapter cards used it extensively. Today, cards like this are sought by hobbyists and technicians maintaining, restoring, or expanding original IBM PC and XT systems, as well as by vintage computing collectors. The card also sees use in systems requiring a period-correct RS-232 interface for legacy serial devices that do not tolerate the electrical differences of modern USB-to-serial adapters.
This IBM 1501485 XM 8-Bit ISA Async Card has been inspected and is in good used condition. The PCB is clean with no visible cracking, burn marks, or damaged traces. The DB25 connector and ISA edge connector both appear intact with no bent or missing pins. Normal light handling wear is present consistent with prior installation in a vintage PC system. Please view our photo set and contact us if you have any questions. Please note: We have multiple units in stock — yours may not be the one shown in the photos, however, it will be similar in condition and function.
Warranty Information
Additional Information
Brand: |
IBM |
Model: |
1501485 XM |
MPN: |
1501485 |
Type: |
8-Bit ISA Asynchronous Serial Card |
SKU: |
41007 |
Bus Interface: |
8-Bit ISA |
UART Chipset: |
National Semiconductor INS8250N-B |
Serial Protocol: |
RS-232 Asynchronous |
Connector Type: |
DB25 (25-pin D-sub) |
Number of Serial Ports: |
1 |
Oscillator Frequency: |
1843.200 KHz (CK1100AC) |
Form Factor: |
Half-Length ISA Card |
Compatible With: |
IBM PC, PC/XT, IBM-compatible 8-bit ISA systems |
Condition: |
Used – Inspected, Good Condition |
Seller Notes: |
Card only; no cables or software included. |
Country/Region of Manufacture: |
Malaysia |
Condition Notes: |
IBM 1501485 XM 8-Bit ISA Async Card. Inspected and in good used condition. PCB clean, DB25 and ISA edge connector intact, no visible damage. Normal light wear from prior use. Card only, no cables. |
