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Black DB-9 male-to-female RS-232 tester with dual-color LED array on each pin

CableMAX

CableMAX DB9-TESTER RS-232 LED Link Tester DB-9 Male to DB-9 Female

SKU CH-XTW1-2S0QM

Tests RS-232 serial links with dual-colour LEDs on every pin, requires no power and works up to 200 Kbps

  • Adapter typeDB9 Gender Changer
  • Product colorBlack
  • Key featuresAllows connection status monitoring for RS-232 Host to Devic
  • Instant diagnostics with dual-colour LEDs on every pin
  • Works with any 9-pin or 25-pin RS-232 serial link
  • No external power needed for portable testing
  • Plug-and-play setup requires no driver installation
  • Compatible with Windows 10, 11, Linux and macOS

What this tester does

The CableMAX DB9-TESTER is a passive RS-232 link tester with a DB-9 male connector on one side and a DB-9 female connector on the other. Dual-colour LEDs on every pin flash to show live transmit and receive activity so engineers and technicians can verify COM-port wiring without opening a case. It draws power directly from the serial line and needs no drivers on Windows 10, 11, Linux or macOS.

Practical limits of the RS-232 interface

The tester handles signals up to 200 Kbps and follows the standard DB-9 pin assignment, including cross-wiring to DB-25 where Pin 2 maps to Pin 3 and Pin 3 to Pin 2. Because it is passive, it cannot boost weak voltages or extend cable runs beyond the normal RS-232 distance envelope. The plastic body measures 1.77 × 1.38 × 0.82 in and weighs 55 g, so it fits in tight back-panel spaces but offers no shielding of its own.

What it replaces and when to upgrade

This unit replaces a breakout box or a multimeter when you only need to confirm that each of the nine lines is toggling. It will not capture or log data, so developers who need full protocol analysis or bit-error testing should use a dedicated analyser instead. The jump is worth it for field service kits and lab benches where instant visual confirmation of DTR, RTS, CTS, DCD and RI states speeds up fault isolation.

How it compares

Measured against everything we stock in Other Adapters & Couplers, at today’s prices. Recalculated every night.

Price $20.99
Pricier than about 60% of the 1,761 comparable items (median $18.99).

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Specifications

Product
Brand nameCableMax
Model nameDB9-TESTER
Product colorBlack
Adapter typeDB9 Gender Changer

Questions about this item

Should I choose a DB-9 or DB-25 version for my serial port?

This single unit covers both; the pin-assignment table maps every DB-9 signal to its DB-25 counterpart so one tester works with either connector type.

What does the 200 Kbps rating mean when I plug it into a live COM port?

It is the maximum signalling speed the LED array can reliably display; faster traffic will still pass through but the lights may not resolve every transition.

Which serial standard does the DB-9 male-to-female interface follow and what does it limit?

The adapter implements the RS-232 DTE/DCE pinout, so it is limited to the voltage levels and 200 Kbps rate defined by that standard.

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