Legacy PC ports: COM1 is typically presented on which connector type on desktop PCs?

Introduction / Context:Serial COM ports on legacy PCs commonly use DE-9 (often called DB-9) connectors. Identifying the correct gender and pin count helps when selecting console cables, null modems, or adapters for serial devices.

Given Data / Assumptions:

• Standard RS-232 implementations on desktop motherboards.
• COM1 and COM2 provided on rear I/O or via bracket headers.
• Gender convention typically male on the system side for DE-9.

Concept / Approach:

Most AT/ATX-era PCs expose COM1 as a 9-pin male D-sub (DE-9M). Older systems sometimes used 25-pin male (DB-25M) for serial, but DE-9M became the norm. Parallel LPT ports generally used 25-pin female (DB-25F), helping distinguish the two.

Step-by-Step Solution:

Verification / Alternative check:

Motherboard manuals and I/O shield legends show COM ports as 9-pin male; serial loopback plugs and console cables fit the male jack with female cable ends.

Why Other Options Are Wrong:

• 15 pin port: Typically VGA (HD-15) or game/MIDI (DA-15), not RS-232 COM1.
• 9 pin female port: The system side is usually male; female ends are on cables.
• 25 pin male port: Was used historically for some serial ports but is not typical for COM1 on most later PCs.
• None of the above: Incorrect because DE-9 male is standard.

Common Pitfalls:

Confusing DB-25 parallel (female) with DB-25 serial (male); using a straight-through cable when a null modem is required for device-to-device connections.

Final Answer:

9 pin male port