[ CABLE / ADAPTER RECORD // EIA/TIA-232 NULL-MODEM ]
RS-232 DB-25 Null-Modem Cable
DE-9 female ends with crossed TXD/RXD and signal ground; RTS/CTS and other handshake crossing varies by cable.
CLASSIFICATION: Serial and converter cables. Identify protocol, direction, pinout and exact cable revision before connection.
Interface and capability
| Standard / protocol | EIA/TIA-232 null-modem, DB-25 |
|---|---|
| Endpoint / pinout | DB-25 ends with crossed TXD/RXD and signal ground; RTS/CTS, DTR/DSR/DCD crossover depends on whether this is 3-wire or full-handshake wiring. |
| Capability / limits | RS-232 does not define one cable baud or reach guarantee; transceiver, capacitance, shielding and environment control reliable operation. |
| Certification / length | Standards define interface requirements, not every assembly’s performance. Certification, mode, current/power rating, direction and maximum length belong to the exact product/revision and complete channel; verify its manufacturer specification. Do not infer certification from connector shape or marketing terminology. |
Compatibility & handling
- A DB-25 null-modem cable is not the existing DE-9 variant or a straight-through modem lead. Verify pin map, DTE/DCE roles and handshake requirements before use; never attach to a TTL UART.
- Inspect connector keying, latch, contact condition, shielding, jacket and model/revision marking. Stop if contacts are bent, loose, scorched, corroded or mismatched.
- Route without tension or sharp bends; follow product bend-radius, strain-relief, current and environmental limits. Test at the intended protocol and mode—physical fit is not a compatibility test.
Sources & further reading
- TIA-232 StandardsPrimary manufacturer or standards reference for EIA/TIA-232 null-modem, DB-25; verify exact model and revision.