[ CABLE / ADAPTER RECORD // EIA/TIA-232 STRAIGHT-THROUGH ]
RS-232 DE-9 Loopback Diagnostic Adapter
DE-9 mapping is pin-to-same-pin for TX/RX, ground and optional handshaking; intended for compatible DTE/DCE pair.

CLASSIFICATION: Serial and converter cables. Identify protocol, direction, pinout and exact cable revision before connection.
Interface and capability
| Standard / protocol | EIA/TIA-232 DE-9 loopback test adapter |
|---|---|
| Endpoint / pinout | DE-9 test plug locally routes transmit to receive (pins 2↔3) and may loop handshake pins (commonly 7↔8); exact jumper set must be documented. |
| Capability / limits | Diagnostic accessory, not an inter-device cable; it tests selected port signals only and does not validate every modem/control line. |
| 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
- Use only as a local test fixture with the specified DTE port. A loopback can make software report a working port while the remote cable/device is faulty; do not connect to a live peer.
- 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 DE-9 loopback test adapter; verify exact model and revision.